Nonhuman primates can be used as models for the study of immune-complex-associated diseases. Recognizing that very little is known about the levels of circulating immune complexes (CICs) in normal monkeys, we have used three assays to measure the levels in serum collected from 313 adult and 106 juvenile cynomolgus macaques (Macaca fascicularis). The prevalence was higher than expected. There was a strong statistical association between CIC levels and country of origin. Monkeys from Indonesia were more likely to have elevated CICs than those from Malaya or the Philippines. This relationship was observed with all three assays. Furthermore, juvenile macaques tended to have lower levels than did adults. This study indicates that it may be important to consider genetic factors, the country of origin, or both when selecting cynomolgus macaques for research on immune-complex-associated diseases.
The levels of malondialdehyde (MDA)-specific antibodies in lupus-prone MRL/ lpr mice of different ages were compared to those against DNA. These mice elicited anti-MDA antibodies earlier and in higher levels that anti-DNA antibodies. The levels of immune complexes containing MDA adducts were also higher in these mice when compared to 3 other non-lupus strains. MDA binding to a 100 kDa serum protein was observed in 3 and 5 month old mice. Immune complexes involving anti-MDA antibodies and MDA adducts may represent an additional mechanism that contributes to disease pathogenesis in these mice.
Antibody labelling to reporter molecules is gaining popularity due to its many potential applications for diagnostics and therapeutics. However, non-directional bioconjugation methods which are commonly used often results in the loss of target binding capabilities. Therefore, a site-specific enzymatic based bioconjugation such as sortase-mediated transpeptidation allows for a more rapid and efficient method of antibody conjugation for diagnostic applications. Here we describe the utilization of sortase A bioconjugation to conjugate a single chain fragment variable (scFv) to the extracellular invertase (invB) from Zymomonas mobilis with the aim of developing an invertase based immunoassay. In addition, conjugation to enhanced green fluorescent protein (eGFP) was also validated to show the flexibility of the method. The invertase conjugated complex was successfully applied for the detection of antibody-antigen interaction using a personal glucose meter (PGM) for assay readout. The setup was used in both a direct and competitive assay highlighting the robustness of the conjugate for assay development. The method provides an alternative conjugation process to allow easy exchange of antibodies to facilitate rapid development of diagnostic assays for various diseases on the PGM platform.
In view of a high prevalence of hepatitis B virus infection in the Malaysian population, indirect immunofluorescence examination for hepatitis B surface antigen (HBsAg) was routinely performed on renal biopsy specimen at the University Hospital, Kuala Lumpur, over a 3-year period. Examination of renal tissue from 259 patients, including 47 with systemic lupus erythematosus (SLE), revealed 43 cases with HBsAg in glomerular immune complexes. A significantly high proportion (30/43) of these were SLE patients. The deposits were granular in nature, situated in both the capillary walls and mesangium and associated with immunoglobulin deposition. Morphological patterns of lupus nephritis involved were focal proliferative (one case), diffuse proliferative (23 cases) and membranous (six cases). None of these patients showed clinical evidence of liver disease. The significance of these findings remains uncertain, but the possibility exists that the hepatitis B virus may have a role in the pathogenesis of SLE in the tropics where both SLE and HBs antigenaemia are common.
A panel of five monoclonal antibodies (MAbs) to the HA1 molecule of the influenza B virus of the Victorian lineage with high virus-neutralizing activity was developed. For identification of the virus neutralizing epitopes in HA1 escape mutants (EM) of the influenza BIShandong/07/97 and B/Malaysia/2506/04 virus were selected using virus- neutralizing antibodies (MAbs). Three EMs had single, two--double and one--triple amino acid substitutions (AAS) in HA1 (H122N, A202E, K203T, K2031, K203N or A317V). In addition, AAS N197S was detected in three EMs. A correlation of AAS identified with peculiarities of interaction of EMs with Mabs was discussed.
Infectious bursal disease (IBD), also known as the Gumboro disease, has been a great
concern for poultry industry worldwide. The first outbreak of IBD due to very virulent (vv) IBD virus
(IBDV) infection in Malaysia was reported in 1991. The major economic impact of the disease is high
mortality and poor performance. The virus causes immunosuppression where if the infected chicken
recovered from the acute disease, they become more susceptible to infections of other pathogens and
fail to respond to vaccines. Therefore, prevention is important and vaccination has become the
principal control measure of IBDV infection in chickens. The conventional attenuated live and killed
vaccines are the most commonly used vaccines. With the advancement of knowledge and technology,
new generation of genetically-engineered vaccines like viral vector and immune complex vaccines
have been commercialised. Moreover, hatchery vaccination is becoming a common practise, in
addition to farm vaccination. Currently, the disease is considerably under controlled with the
introduction of vaccination. However, occasional field outbreaks are still commonly reported. The
demand for vaccines that could suit the field situation continues to exist. The endemicity of disease,
presence of challenge in the farm and maternally derived antibody in chicks are affecting the choice
vaccine as well as the vaccine development and vaccination strategies. In this review, advances made
in various vaccines that have been commercialised or under development, and challenges that they
face, are outlined. Furthermore, how the emergence of vvIBDV affect the progress of vaccine
development and influence its vaccination strategy are discussed.
Systemic lupus erythematosus (SLE) is an autoimmune disorder that is associated with lupus nephritis, initiated by the deposition of immune complexes in the kidney; subsequently, this induces the overexpression of cytokines. Lupus nephritis is known as one of the major clinical manifestations that affect the disease severity in SLE patients. An increased number of resident periglomerular and immune cells in the kidney has the potential to affect the equilibrium of different immune cell subsets, such as Th1, Th2, Th17, and Tregs, which may be central to the induction of tissue damage in kidney by exerting either proinflammatory or anti-inflammatory effects, or both. This equilibrium has yet to be confirmed, as new players such as IL-25 remain undiscovered. IL-25 is a cytokine of the IL-17 family, which stimulates Th2-mediated immune response when overly expressed. Thus, the aim of this research is to determine the plasma levels of IL-25 and Th2-associated cytokines (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13) in SLE patients with (SLE-LN) and without lupus nephritis. Sixty-four (n = 64) SLE patients and fifteen (n = 15) healthy individuals were recruited. This study demonstrated that the IL-9, IL-10 and IL-25 had significantly increased expressions in SLE-LN, followed by SLE without LN, compared to healthy controls. Meanwhile, IL-5 and IL-6 had significantly reduced. No significant difference was observed with IL-13, while the level of IL-4 was undetectable. Furthermore, IL-9 and IL-10 were significantly correlated with the IL-25, and IL-25, IL-9 and IL-10 were positively correlated with the disease severity score, SLEDAI. In conclusion, IL-25 and its associated Th2 cytokines (IL-9 and IL-10) may be involved in SLE pathogenesis. These cytokines could be potential biomarkers in monitoring and predicting the disease severity during SLE pathogenesis.
The lymphatic filarial parasites which affect about 90 million people worldwide have similar host-parasite relationships in man. They are all able to survive, reproduce and cause chronic infections if they can successfully evade the protective responses of the host. Studies to investigate the wide spectrum of clinical manifestations of the infection even among those living in similar endemic areas and with presumed equal exposure to infective larvae, have been hampered by the lack of animal models showing similar host-parasite responses. The recent use of the nude mouse infected with Brugia spp, and the leaf-monkey (Presbytis spp) infected with B. malayi or Wuchereria spp for the study of immune responses and the associated pathology of these infections, has elucidated some of the host protective immune responses as well as the associated immunopathological reactions. The successfully entrenched parasite elicits minimal reactions and pathology, but with the onset of effective host responses, whether assisted by chemotherapy, development of protective immunity or both, severe inflammatory responses may occur. The role of such immune mediated response in determining subsequent pathology will probably be dependent on the frequency and duration of these episodes, but these have yet to be defined. Prenatal and perinatal sensitization by filarial antigens are postulated to result in tolerance and/or modification of immune responses to subsequent infections. A role for genetic predisposition to certain clinical outcomes, for example, the development of elephantiasis, has been postulated but needs further study. Advances have also been achieved in defining those parasite antigens/products involved in eliciting or suppressing protective and other immune responses.(ABSTRACT TRUNCATED AT 250 WORDS)
The development of antibody-based biosensor has grown steadily during recent years, and their use as a routine instrument in clinical application is not far from reality. This study has demonstrated the capability of conductometric sensor to quantitate human Follicle Stimulating Hormone (hFSH) from urine samples. The principles are adopted from Enzyme Linked Immunosorbent Assay (ELISA) technique. Self fabricated gold coated electrode was dipped in the microtiter well containing antibody-antigen complex. Substrate was added to the system to initiate a secondary reaction, which produced electroactive species and change the conductivity of the solution. The changes were proportional with the concentration of the hormone present. The results obtained correlate well with the conventional ELISA technique. Inter and intra assay variation (%CV) were under 6% and the lowest detection limit is 0.75 mIU/ml which was well under the physiological range of the hormone. This system offered advantages such as simplicity, reliability, minimal addition of reagents, freedom from turbidity and color problem, probability of miniaturizing the electrode thus minimizing the sample volume and the ability of on line data analysis. This study proved that Antigen-Antibody reaction via EIA could be detected electronically and it has a potential to be used as one of the measuring mode in clinical analysis.
Dexamethasone has recently been shown to block the production of cachectin (implicated in the pathogenesis of cerebral malaria) if administered prior to endotoxin induction of mouse macrophages. Using the hamster cheek pouch-cerebral malaria model, we tested the hypothesis that dexamethasone is effective as a therapeutic agent in severe malaria if given before some yet undefined trigger point in the disease. Infected hamsters were treated with dexamethasone (0.7 mg/kg) daily on days 7-12, 4-12, or 1-12 post-challenge. When treatment was started on day 1, whole body oxygen consumption (used as a measure of erythrocyte transport to sites of diffusion) on day 12 was greater than (P less than 0.05) that of infected control animals, though the degree of anemia was no different in treated and untreated groups. Furthermore, treatment produced a reduction in monocyte accumulation, capillary malfunction, and monocyte/red blood cell aggregate formation observable in the cheek pouch in vivo and a similar reduction in monocyte presence, capillary pathologic change, and multifocal hemorrhage in the brain on postmortem. These data suggest that mediator(s), whose production can be blocked by pretreatment with dexamethasone, are involved in the pathogenesis of disease leading to death of the Plasmodium berghei infected hamster.