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Frontiers of monoclonal antibodies: Applications in medical practices

Ghagane SC, Puranik SI, Gan SH, Hiremath MB, Nerli RB, Ravishankar MV

Hum Antibodies, 2017;26(3):135-142.
PMID: 29060935 DOI: 10.3233/HAB-170331

With the flourishing of innovation in drug discovery into a new era of personalized therapy, the use of monoclonal antibodies (mAbs) in the treatment of various ailments lies at the forefront. Major improvements in genetic sequencing and biomedical techniques as well as research into mAbs emphasize on determining new targets for advanced therapy while maximizing efficacy for clinical application. However, a balance has to be achieved concerning developing a target with low toxicity combined with high specificity and versatility, to allow a specific antibody to facilitate several biotic effects, ranging from neutralization of virus mechanisms to modulation of immune response and maintaining low global economic cost. Presently, there are approximately 30 mAbs' permitted for therapeutic use with many more being tested in clinical trials. Nevertheless, the heavy cost of mAbs' production, stowage and management as well as the subsequent hindrances to their development are outweighed by mAbs' clinical advantages. Compared to conventional drugs, since mAbs use as pharmacologic iotas have specific physical features and modes of action, they should be considered as a discrete therapeutic category. In this review, the history of mAb generation and the innovative technological applications of mAbs that has advanced in clinical practices is reviewed.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Characterization of SARS-CoV-2 worldwide transmission based on evolutionary dynamics and specific viral mutations in the spike protein

Liu J, Chen X, Liu Y, Lin J, Shen J, Zhang H, et al.

Infect Dis Poverty, 2021 Aug 21;10(1):112.
PMID: 34419160 DOI: 10.1186/s40249-021-00895-4

BACKGROUND: The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) is pandemic. However, the origins and global transmission pattern of SARS-CoV-2 remain largely unknown. We aimed to characterize the origination and transmission of SARS-CoV-2 based on evolutionary dynamics.
METHODS: Using the full-length sequences of SARS-CoV-2 with intact geographic, demographic, and temporal information worldwide from the GISAID database during 26 December 2019 and 30 November 2020, we constructed the transmission tree to depict the evolutionary process by the R package "outbreaker". The affinity of the mutated receptor-binding region of the spike protein to angiotensin-converting enzyme 2 (ACE2) was predicted using mCSM-PPI2 software. Viral infectivity and antigenicity were tested in ACE2-transfected HEK293T cells by pseudovirus transfection and neutralizing antibody test.
RESULTS: From 26 December 2019 to 8 March 2020, early stage of the COVID-19 pandemic, SARS-CoV-2 strains identified worldwide were mainly composed of three clusters: the Europe-based cluster including two USA-based sub-clusters; the Asia-based cluster including isolates in China, Japan, the USA, Singapore, Australia, Malaysia, and Italy; and the USA-based cluster. The SARS-CoV-2 strains identified in the USA formed four independent clades while those identified in China formed one clade. After 8 March 2020, the clusters of SARS-CoV-2 strains tended to be independent and became "pure" in each of the major countries. Twenty-two of 60 mutations in the receptor-binding domain of the spike protein were predicted to increase the binding affinity of SARS-CoV-2 to ACE2. Of all predicted mutants, the number of E484K was the largest one with 86 585 sequences, followed by S477N with 55 442 sequences worldwide. In more than ten countries, the frequencies of the isolates with E484K and S477N increased significantly. V367F and N354D mutations increased the infectivity of SARS-CoV-2 pseudoviruses (P

Matched MeSH terms: Antibodies, Neutralizing/immunology
Identification and characterization of neutralization epitopes at VP2 and VP1 of enterovirus A71

NikNadia N, Tan CW, Ong KC, Sam IC, Chan YF

J Med Virol, 2018 06;90(6):1164-1167.
PMID: 29457642 DOI: 10.1002/jmv.25061

Enterovirus A71 (EV-A71) neutralization escape mutants were generated with monoclonal antibody MAB979 (Millipore). The VP2-T141I and VP1-D14N substitutions were identified. Using reverse genetics, infectious clones with these substitutions were constructed and tested by neutralization assay with immune sera from mice and humans. The N-terminus VP1-14 is more important than EF loop VP2-141 in acute human infection, mainly because it recognised IgM present in acute infection. The N-terminus VP1 could be a useful target for diagnostics and therapeutic antibodies in acute infection.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Fulltext Advances in Antigenic Peptide-Based Vaccine and Neutralizing Antibodies against Viruses Causing Hand, Foot, and Mouth Disease

Anasir MI, Poh CL

Int J Mol Sci, 2019 Mar 13;20(6).
PMID: 30871133 DOI: 10.3390/ijms20061256

Hand, foot, and mouth disease (HFMD) commonly produces herpangina, but fatal neurological complications have been observed in children. Enterovirus 71 (EV-A71) and Coxsackievirus 16 (CV-A16) are the predominant viruses causing HFMD worldwide. With rising concern about HFMD outbreaks, there is a need for an effective vaccine against EV-A71 and CV-A16. Although an inactivated vaccine has been developed against EV-A71 in China, the inability of the inactivated vaccine to confer protection against CV-A16 infection and other HFMD etiological agents, such as CV-A6 and CV-A10, necessitates the exploration of other vaccine platforms. Thus, the antigenic peptide-based vaccines are promising platforms to develop safe and efficacious multivalent vaccines, while the monoclonal antibodies are viable therapeutic and prophylactic agents against HFMD etiological agents. This article reviews the available information related to the antigenic peptides of the etiological agents of HFMD and their neutralizing antibodies that can provide a basis for the design of future therapies against HFMD etiological agents.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Fulltext A broadly neutralizing germline-like human monoclonal antibody against dengue virus envelope domain III

Hu D, Zhu Z, Li S, Deng Y, Wu Y, Zhang N, et al.

PLoS Pathog, 2019 06;15(6):e1007836.
PMID: 31242272 DOI: 10.1371/journal.ppat.1007836

Dengue is the most widespread vector-borne viral disease caused by dengue virus (DENV) for which there are no safe, effective drugs approved for clinical use. Here, by using sequential antigen panning of a yeast antibody library derived from healthy donors against the DENV envelop protein domain III (DIII) combined with depletion by an entry defective DIII mutant, we identified a cross-reactive human monoclonal antibody (mAb), m366.6, which bound with high affinity to DENV DIII from all four DENV serotypes. Immunogenetic analysis indicated that m366.6 is a germline-like mAb with very few somatic mutations from the closest VH and Vλ germline genes. Importantly, we demonstrated that it potently neutralized DENV both in vitro and in the mouse models of DENV infection without detectable antibody-dependent enhancement (ADE) effect. The epitope of m366.6 was mapped to the highly conserved regions on DIII, which may guide the design of effective dengue vaccine immunogens. Furthermore, as the first germline-like mAb derived from a naïve antibody library that could neutralize all four DENV serotypes, the m366.6 can be a tool for exploring mechanisms of DENV infection, and is a promising therapeutic candidate.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Fulltext The neutralizing role of IgM during early Chikungunya virus infection

Chua CL, Sam IC, Chiam CW, Chan YF

PLoS One, 2017;12(2):e0171989.
PMID: 28182795 DOI: 10.1371/journal.pone.0171989

The antibody isotype IgM appears earlier than IgG, within days of onset of symptoms, and is important during the early stages of the adaptive immune response. Little is known about the functional role of IgM during infection with chikungunya virus (CHIKV), a recently reemerging arbovirus that has caused large global outbreaks. In this study, we studied antibody responses in 102 serum samples collected during CHIKV outbreaks in Malaysia. We described the neutralizing role of IgM at different times post-infection and examined the independent contributions of IgM and IgG towards the neutralizing capacity of human immune sera during the early phase of infection, including the differences in targets of neutralizing epitopes. Neutralizing IgM starts to appear as early as day 4 of symptoms, and their appearance from day 6 is associated with a reduction in viremia. IgM acts in a complementary manner with the early IgG, but plays the main neutralizing role up to a point between days 4 and 10 which varies between individuals. After this point, total neutralizing capacity is attributable almost entirely to the robust neutralizing IgG response. IgM preferentially binds and targets epitopes on the CHIKV surface E1-E2 glycoproteins, rather than individual E1 or E2. These findings provide insight into the early antibody responses to CHIKV, and have implications for design of diagnostic serological assays.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Fulltext N-terminal domain of SARS CoV-2 spike protein mutation associated reduction in effectivity of neutralizing antibody with vaccinated individuals

Singh Y, Fuloria NK, Fuloria S, Subramaniyan V, Meenakshi DU, Chakravarthi S, et al.

J Med Virol, 2021 Oct;93(10):5726-5728.
PMID: 34232521 DOI: 10.1002/jmv.27181
Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Structural Evaluation of the Spike Glycoprotein Variants on SARS-CoV-2 Transmission and Immune Evasion

Salleh MZ, Derrick JP, Deris ZZ

Int J Mol Sci, 2021 Jul 10;22(14).
PMID: 34299045 DOI: 10.3390/ijms22147425

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents significant social, economic and political challenges worldwide. SARS-CoV-2 has caused over 3.5 million deaths since late 2019. Mutations in the spike (S) glycoprotein are of particular concern because it harbours the domain which recognises the angiotensin-converting enzyme 2 (ACE2) receptor and is the target for neutralising antibodies. Mutations in the S protein may induce alterations in the surface spike structures, changing the conformational B-cell epitopes and leading to a potential reduction in vaccine efficacy. Here, we summarise how the more important variants of SARS-CoV-2, which include cluster 5, lineages B.1.1.7 (Alpha variant), B.1.351 (Beta), P.1 (B.1.1.28/Gamma), B.1.427/B.1.429 (Epsilon), B.1.526 (Iota) and B.1.617.2 (Delta) confer mutations in their respective spike proteins which enhance viral fitness by improving binding affinity to the ACE2 receptor and lead to an increase in infectivity and transmission. We further discuss how these spike protein mutations provide resistance against immune responses, either acquired naturally or induced by vaccination. This information will be valuable in guiding the development of vaccines and other therapeutics for protection against the ongoing coronavirus disease 2019 (COVID-19) pandemic.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Formaldehyde-inactivated whole-virus vaccine protects a murine model of enterovirus 71 encephalomyelitis against disease

Ong KC, Devi S, Cardosa MJ, Wong KT

J Virol, 2010 Jan;84(1):661-5.
PMID: 19864378 DOI: 10.1128/JVI.00999-09

Enterovirus 71 (EV71) causes childhood hand, foot, and mouth disease and neurological complications, and no vaccines or therapeutic drugs are currently available. Formaldehyde-inactivated whole-virus vaccines derived from EV71 clinical isolates and a mouse-adapted virus (MAV) were tested in a mouse model of EV71 encephalomyelitis. After only two immunizations, given to mice at 1 and 7 days of age, the MAV vaccine protected mice at 14 days of age from disease. Tissues from immunized mice were negative for virus by viral culture, reverse transcriptase PCR, immunohistochemistry analysis, and in situ hybridization. Cross-neutralizing EV71 antibodies to strains with genotypes B3, B4, and C1 to C5 generated in immunized adult mice were able to passively protect 14-day-old mice from disease.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Immunological cross-reactivity and neutralization of the principal toxins of Naja sumatrana and related cobra venoms by a Thai polyvalent antivenom (Neuro Polyvalent Snake Antivenom)

Leong PK, Fung SY, Tan CH, Sim SM, Tan NH

Acta Trop, 2015 Sep;149:86-93.
PMID: 26026717 DOI: 10.1016/j.actatropica.2015.05.020

The low potency of cobra antivenom has been an area of concern in immunotherapy for cobra envenomation. This study sought to investigate factors limiting the neutralizing potency of cobra antivenom, using a murine model. We examined the immunological reactivity and neutralizing potency of a Thai polyvalent antivenom against the principal toxins of Naja sumatrana (Equatorial spitting cobra) venom and two related Asiatic cobra venom α-neurotoxins. The antivenom possesses moderate neutralizing potency against phospholipases A2 (P, potency of 0.98mg/mL) and moderately weak neutralizing potency against long-chain α-neurotoxins (0.26-0.42mg/mL) but was only weakly effective in neutralizing the short-chain α-neurotoxins and cardiotoxins (0.05-0.08mg/mL). The poor neutralizing potency of the antivenom on the low molecular mass short-chain neurotoxins and cardiotoxins is presumably the main limiting factor of the efficacy of the cobra antivenom. Our results also showed that phospholipase A2, which exhibited the highest ELISA reactivity and avidity, was most effectively neutralized, whereas N. sumatrana short-chain neurotoxin, which exhibited the lowest ELISA reactivity and avidity, was least effectively neutralized by the antivenom. These observations suggest that low immunoreactivity (low ELISA reactivity and avidity) is one of the reasons for poor neutralization of the cobra venom low molecular mass toxins. Nevertheless, the overall results show that there is a lack of congruence between the immunological reactivity of the toxins toward antivenom and the effectiveness of toxin neutralization by the antivenom, indicating that there are other factors that also contribute to the weak neutralization capacity of the antivenom. Several suggestions have been put forward to overcome the low efficacy of the cobra antivenom. The use of a 'proper-mix' formulation of cobra venoms as immunogen, whereby the immunogen mixture used for hyperimmunization contains a mix of various types of α-neurotoxins and cardiotoxins in sufficient amount, may also help to improve the efficacy and broaden the neutralization spectrum of the antivenom.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Cross neutralization of common Southeast Asian viperid venoms by a Thai polyvalent snake antivenom (Hemato Polyvalent Snake Antivenom)

Leong PK, Tan CH, Sim SM, Fung SY, Sumana K, Sitprija V, et al.

Acta Trop, 2014 Apr;132:7-14.
PMID: 24384454 DOI: 10.1016/j.actatropica.2013.12.015

Snake envenomation is a serious public health threat in many rural areas of Asia and Africa. Antivenom has hitherto been the definite treatment for snake envenomation. Owing to a lack of local production of specific antivenom, most countries in these regions fully depend on foreign supplies of antivenoms. Often, the effectiveness of the imported antivenoms against local medically important species has not been validated. This study aimed to assess cross-neutralizing capacity of a recently developed polyvalent antivenom, Hemato Polyvalent Snake Antivenom (HPAV), against venoms of a common viper and some pit vipers from Southeast Asia. Neutralisation assays showed that HPAV was able to effectively neutralize lethality of the common Southeast Asian viperid venoms examined (Calloselasma, Crytelytrops, Popeia, and Daboia sp.) except for Tropidolaemus wagleri venom. HPAV also effectively neutralized the procoagulant and hemorrhagic activities of all the venoms examined, corroboratively supporting the capability of HPAV in neutralizing viperid venoms which are principally hematoxic. The study also indicated that HPAV fully prevented the occurrence of hematuria and proteinuria in mice envenomed with Thai Daboia siamensis venom but was only partially effective against venoms of Myanmar D. siamensis. Thus, HPAV appears to be useful against its homologous venoms and venoms from Southeast Asian viperids including several medically important pit vipers belonging to the Trimeresurus complex. Nevertheless, the effectiveness of HPAV as a paraspecific antivenom for treatment of viperid envenomation in Southeast Asian region requires further assessment from future clinical trials.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Evaluation of neutralizing antibodies produced by papaya mosaic virus nanoparticles fused to the E2EP3 peptide epitope of Chikungunya envelope

Nor Rashid N, Teoh TC, Al-Harbi SJ, Yusof R, Rothan HA

Trop Biomed, 2021 Mar 01;38(1):36-41.
PMID: 33797522 DOI: 10.47665/tb.38.1.007

Chikungunya virus (CHIKV) infection is the cause of acute symptoms and chronic symmetrical polyarthritis associated with long-term morbidity and mortality. Currently, there is no available licensed vaccine or particularly useful drug for human use against CHIKV infection. This study was conducted to evaluate the efficacy of antibodies produced by papaya mosaic virus (PapMV) nanoparticles fused to E2EP3 peptide of CHIKV envelope as a recombinant CHIKV vaccine. PapMV, PapMV-C- E2EP3, and E2EP3-N-PapMV were produced in E. coli with an approximate size of 27 to 30 kDa. ICR mice (5 to 6 weeks of age) were injected subcutaneously with 25 micrograms of vaccine construct, and ELISA measured the titer of CHIKV specific IgG antibodies. The results showed that both recombinant proteins E2EP3-N-PapMV and PapMVC-E2EP3 were able to induce IgG antibodies production in immunized mice against CHIKV while immunization with recombinant PapMV showed no IgG antibodies induction. The neutralizing activity of the antibodies generated by either E2EP3-N-PapMV or PapMV-C-E2EP3 exhibited similar inhibition to CHIKV replication in Vero cells using the cells based antibody neutralizing assay and analyzed by plaque formation assay. This study showed the effectiveness of nanoparticles vaccine generated by fusing epitope peptide of CHIKV envelope to papaya mosaic virus envelope in inducing a robust immune response in mice against CHIKV. The data showed that levels of neutralizing antibodies correlate with a protective immune response CHIKV replication.

Matched MeSH terms: Antibodies, Neutralizing/immunology*
Fulltext A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)

Wong KY, Tan KY, Tan NH, Tan CH

Toxins (Basel), 2021 01 14;13(1).
PMID: 33466660 DOI: 10.3390/toxins13010060

The Senegalese cobra, Naja senegalensis, is a non-spitting cobra species newly erected from the Naja haje complex. Naja senegalensis causes neurotoxic envenomation in Western Africa but its venom properties remain underexplored. Applying a protein decomplexation proteomic approach, this study unveiled the unique complexity of the venom composition. Three-finger toxins constituted the major component, accounting for 75.91% of total venom proteins. Of these, cardiotoxin/cytotoxin (~53%) and alpha-neurotoxins (~23%) predominated in the venom proteome. Phospholipase A2, however, was not present in the venom, suggesting a unique snake venom phenotype found in this species. The venom, despite the absence of PLA2, is highly lethal with an intravenous LD50 of 0.39 µg/g in mice, consistent with the high abundance of alpha-neurotoxins (predominating long neurotoxins) in the venom. The hetero-specific VINS African Polyvalent Antivenom (VAPAV) was immunoreactive to the venom, implying conserved protein antigenicity in the venoms of N. senegalensis and N. haje. Furthermore, VAPAV was able to cross-neutralize the lethal effect of N. senegalensis venom but the potency was limited (0.59 mg venom completely neutralized per mL antivenom, or ~82 LD50 per ml of antivenom). The efficacy of antivenom should be further improved to optimize the treatment of cobra bite envenomation in Africa.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Dengue virus infection-enhancing activity in serum samples with neutralizing activity as determined by using FcγR-expressing cells

Moi ML, Lim CK, Chua KB, Takasaki T, Kurane I

PLoS Negl Trop Dis, 2012;6(2):e1536.
PMID: 22389741 DOI: 10.1371/journal.pntd.0001536

Progress in dengue vaccine development has been hampered by limited understanding of protective immunity against dengue virus infection. Conventional neutralizing antibody titration assays that use FcγR-negative cells do not consider possible infection-enhancement activity. We reasoned that as FcγR-expressing cells are the major target cells of dengue virus, neutralizing antibody titration assays using FcγR-expressing cells that determine the sum of neutralizing and infection-enhancing activity, may better reflect the biological properties of antibodies in vivo.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Risk Factors for Nipah virus infection among pteropid bats, Peninsular Malaysia

Rahman SA, Hassan L, Epstein JH, Mamat ZC, Yatim AM, Hassan SS, et al.

Emerg Infect Dis, 2013 Jan;19(1):51-60.
PMID: 23261015 DOI: 10.3201/eid1901.120221

We conducted cross-sectional and longitudinal studies to determine the distribution of and risk factors for seropositivity to Nipah virus (NiV) among Pteropus vampyrus and P. hypomelanus bats in Peninsular Malaysia. Neutralizing antibodies against NiV were detected at most locations surveyed. We observed a consistently higher NiV risk (odds ratio 3.9) and seroprevalence (32.8%) for P. vampyrus than P. hypomelanus (11.1%) bats. A 3-year longitudinal study of P. hypomelanus bats indicated nonseasonal temporal variation in seroprevalence, evidence for viral circulation within the study period, and an overall NiV seroprevalence of 9.8%. The seroprevalence fluctuated over the study duration between 1% and 20% and generally decreased during 2004-2006. Adult bats, particularly pregnant, with dependent pup and lactating bats, had a higher prevalence of NiV antibodies than juveniles. Antibodies in juveniles 6 months-2 years of age suggested viral circulation within the study period.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Human adenovirus type 8: the major agent of epidemic keratoconjunctivitis (EKC)

Adhikary AK, Banik U

J Clin Virol, 2014 Dec;61(4):477-86.
PMID: 25464969 DOI: 10.1016/j.jcv.2014.10.015

Human adenovirus type 8 (HAdV-8) is the most common causative agent of a highly contagious eye disease known as epidemic keratoconjunctivitis (EKC). HAdV-8 strains have been classified into genome types HAdV-8A to 8K and HAdV/D1 to D12 according to restriction endonuclease analysis. This review focuses on the significance of HAdV-8 as an agent of EKC. Molecular analysis of HAdV-8 genome types HAdV-53 and HAdV-54 was performed to reveal potential genetic variation in the hexon and fiber, which might affect the antigenicity and tropism of the virus, respectively. On the basis of the published data, three patterns of HAdV-8 genome type distribution were observed worldwide: (1) genome types restricted to a microenvironment, (2) genome types distributed within a country, and (3) globally dispersed genome types. Simplot and zPicture showed that the HAdV-8 genome types were nearly identical to each other. HAdV-54 is very close to the HAdV-8P, B and E genomes, except in the hexon. In a restriction map, HAdV-8P, B, and E share a very high percentage of restriction sites with each other. Hypervariable regions (HVRs) of the hexon were conserved and were 100% identical among the genome types. The fiber knob of HAdV-8P, A, E, J and HAdV-53 were 100% identical. In phylogeny, HVRs of the hexon and fiber knob of the HAdV-8 genome types segregated into monophyletic clusters. Neutralizing antibodies against one genome type will provide protection against other genome types, and the selection of future vaccine strains would be simple due to the stable HVRs. Molecular analysis of whole genomes, particularly of the capsid proteins of the remaining genome types, would be useful to substantiate our observations.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Dengue patients exhibit higher levels of PrM and E antibodies than their asymptomatic counterparts

Yeo AS, Rathakrishnan A, Wang SM, Ponnampalavanar S, Manikam R, Sathar J, et al.

Biomed Res Int, 2015;2015:420867.
PMID: 25815314 DOI: 10.1155/2015/420867

Dengue virus infection is a common tropical disease which often occurs without being detected. These asymptomatic cases provide information in relation to the manifestation of immunological aspects. In this study, we developed an ELISA method to compare neutralizing effects of dengue prM and E antibodies between dengue patients and their asymptomatic household members. Recombinant D2 premembrane (prM) was constructed, cloned, and tested for antigenicity. The recombinant protein was purified and tested with controls by using an indirect ELISA method. Positive dengue serum samples with their asymptomatic pair were then carried out onto the developed ELISA. In addition, commercially available recombinant envelope (E) protein was used to develop an ELISA which was tested with the same set of serum samples in the prM ELISA. Asymptomatic individuals showed preexisting heterotypic neutralizing antibodies. The recombinant prM was antigenically reactive in the developed ELISA. Dengue patients had higher prM and E antibodies compared to their household members. Our study highlights the neutralizing antibodies levels with respect to dengue prM and E between dengue patients and asymptomatic individuals.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Mixing versus matching booster vaccines: Longitudinal humoral immune kinetics against Omicron in a Malaysian cohort

Thundakattil AV, Prabhu R, Prabhu G, Mani M, De S, Soe HHK, et al.

Int J Infect Dis, 2026 Nov;172:109103.
PMID: 42697472 DOI: 10.1016/j.ijid.2026.109103

OBJECTIVES: The objective of our study was to evaluate the longitudinal humoral immune response following booster regimens in Malaysia during the Omicron outbreak.
METHODS: In this prospective cohort study, 268 healthcare professionals and medical students in Malaysia were followed up for 24 weeks following homologous (messenger ribonucleic acid [mRNA]-mRNA [mR-mR], viral vector-viral vector [VV-VV], inactivated virus-inactivated virus [IV-IV]) and heterologous (inactivated virus-mRNA [IV-mR], viral vector-mRNA [VV-mR]) booster vaccines. Of them, 190 recipients underwent a longitudinal immunogenicity study. Anti-spike (anti-S) immunoglobulin G (IgG) and anti-receptor-binding domain (anti-RBD) responses were assessed by the ADVIA Centaur severe acute respiratory syndrome coronavirus 2 chemiluminescent immunoassay followed by a surrogate virus neutralization test using the Omicron variant across all boosters.
RESULTS: Compared to homologous boosters, heterologous regimens, particularly the IV-mR booster, elicited significantly higher and sustained anti-S IgG and anti-RBD antibody (P < 0.0001) responses. Over 24 weeks, the heterologous IV-mR booster group had 100% seropositivity for anti-S IgG and anti-RBD antibodies; conversely, in the homologous (IV-IV) booster group, the seropositivity of anti-S IgG and anti-RBD antibodies decreased to 15.63% and 18.75%, respectively. Omicron virus-neutralizing was observed to be as high as 95.92% (IV-mR) and 83.87% (VV-mR) at week 24 after the heterologous booster, while virus neutralization was found to be as low as 9.38% in the IV-IV homologous booster. Age, gender, and ethnicity were not found to be confounding factors for antibody kinetics following a booster vaccine.
CONCLUSION: In conclusion, heterologous booster vaccines induced a superior prolonged humoral immune response against coronavirus disease 2019 infection.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Fulltext Worldwide increased prevalence of human adenovirus type 3 (HAdV-3) respiratory infections is well correlated with heterogeneous hypervariable regions (HVRs) of hexon

Haque E, Banik U, Monwar T, Anthony L, Adhikary AK

PLoS One, 2018;13(3):e0194516.
PMID: 29590206 DOI: 10.1371/journal.pone.0194516

Human adenovirus type 3 (HAdV-3) respiratory infections occurs worldwide in both children and adults, leading to severe morbidity and mortality, particularly in the paediatric age group and especially in neonates. During HAdV infection, neutralizing antibodies are formed against the epitopes located in the hyper variable regions (HVRs) of the hexon protein. These neutralizing antibodies provide protection against reinfection by viruses of the same type. Therefore it is reasonable to speculate that variations of HAdV-3 in the HVRs could impair the immunity acquired by previous infection with a different strain with variation in its HVRs. HAdV-3 has recently become the major agent of acute respiratory infection worldwide, being responsible for 15% to 87% of all adenoviral respiratory infections. However, despite the increased prevalence of HAdV-3 as respiratory pathogen, the diversity of hexon proteins in circulating strains remains unexplored. This study was designed to explore the variation in HVRs of hexon among globally distributed strains of HAdV-3 as well as to discover possible relationship among them, thus possibly shedding light on the cause for the increased prevalence of HAdV-3. In this study, for the first time we analysed the hexon proteins of all 248 available strains of HAdV-3 from the NCBI database and compared them with those of the HAdV-3 prototype (GB stain). We found that the HVRs of HAdV-3 strains circulating worldwide were highly heterogeneous and have been mutating continuously since -their original isolation. Based on their immense heterogeneity, the strains can be categorized into 25 hexon variants (3Hv-1 to 3Hv-25), 4 of which (3Hv-1 to 3Hv-4) comprises 80% of the strains. This heterogeneity may explain why HAdV-3 has become the most prevalent HAdVs type worldwide. The heterogeneity of hexon proteins also shows that the development of a vaccine against HAdV-3 might be challenging. The data on hexon variants provided here may be useful for the future epidemiological study of HAdV-3 infection.

Matched MeSH terms: Antibodies, Neutralizing/immunology
Sera of patients with systemic lupus erythematosus cross-neutralizes dengue viruses

Zainal N, Tan KK, Johari J, Hussein H, Wan Musa WR, Hassan J, et al.

Microbiol. Immunol., 2018 Oct;62(10):659-672.
PMID: 30259549 DOI: 10.1111/1348-0421.12652

Dengue is the most prevalent mosquito-borne disease in Southeast Asia, where the incidence of systemic lupus erythematosus (SLE) is approximately 30 to 53 per 100,000. Severe dengue, however, is rarely reported among individuals with SLE. Here, whether sera of patients with SLE cross-neutralize dengue virus (DENV) was investigated. Serum samples were obtained from individuals with SLE who were dengue IgG and IgM serology negative. Neutralization assays were performed against the three major DENV serotypes. Of the dengue serology negative sera of individuals with SLE, 60%, 61% and 52% of the sera at 1/320 dilution showed more than 50% inhibition against dengue type-1 virus (DENV-1), DENV-2 and DENV-3, respectively. The neutralizing capacity of the sera was significantly greater against DENV-1 (P

Matched MeSH terms: Antibodies, Neutralizing/immunology*

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