Peritoneal macrophages from Mesocestoides corti-infected mice showed a marked and progressive loss of ability to act as accessory cells for syngeneic Con A-stimulated mesenteric lymph node lymphocytes. The same effect on the macrophages could be induced by intraperitoneal injection of M. corti culture supernatant, despite a concurrent increase in numbers of peritoneal adhesive macrophages. The findings are used to compare and contrast the known immunomodulatory effects of M. corti and taeniid metacestodes, the latter differing chiefly in their potential for modifying T-cell as well as macrophage behaviour.

Immunomodulation of macrophage activity by in vitro secretions of Mesocestoides corti has been previously demonstrated. The modifying activity secreted by M. corti had the effect of reducing the normal accessory function of macrophages in a Con-A-activated lymphocyte proliferation assay. This paper describes the purification of the modifying activity by FPLC techniques and the generation of a monoclonal antibody (MoAb) to this molecule in mice. The MoAb bound immunomodulatory FPLC fractions of M. corti in an ELISA. When MoAb was applied in conjunction with immunomodulatory parasite secretions to macrophages in vivo or in vitro, the modifying effect of the secretions was abolished. This profound effect of the MoAb should help to elucidate the mechanisms by which metacestode parasites avoid host immune responses and may enable therapeutic intervention.

Efforts were made to see the effect of feeding aflatoxin B1 at 0.3 ppm level on various aspects of the immune system in chickens. The birds were fed aflatoxin B1 (AFB1) mixed ration from 0 to 6 weeks of age and thereafter normal feed was given up to 12 weeks of age. The delayed type hypersensitivity reaction of these birds was assessed by contact sensitivity to Dinitrofluorobenzene. The dietary AFB1 significantly suppressed the cell mediated immune response at all the three periods tested (30, 45 and 60 days of age). The toxin showed residual effect on immunity as the suppression of cell mediated immunity was maximum three days after the withdrawal of toxin from the feed. The effect of AFB1 on the phagocytic status of reticulo endothelial system (RES) was assessed by colloidal carbon clearance test at various intervals. The residual effect of toxin was observed on RES too as phagocytic index of AFB1 fed birds was significantly lowered up to 45 days of age.

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Foot and mouth disease is an economically important transboundary disease of wildlife and cloven hoofed animals including ruminants. In the absence of vaccination, detection of antibodies against structural proteins (SPs) of foot-and-mouth disease virus is an indicator of infection. In the present study, a rapid dot blot assay using gold nanoparticlees was developed for the detection of antibodies against SPs of FMDV. Commercially available FMD vaccine was used as a source of FMD antigen. After the synthesis of gold nanoparticles (GNPs), the GNP-dot blot assay was tested and was found very sensitive, as the detection of antibody was up to 10 of serum dilution. The GNP-dot assay was found specific as it didn't give dot with normal horse sera, fetal bovine sera and neonatal bovine calf serum samples when tested at 10 working dilution. When 30 serum samples from post-vaccinated buffaloes were tested at dilution of 10, all the samples were found positive with the variable intensity of dot. The synthesized GNPs and conjugated GNPS with antibody were characterized for their absorption limit, for their stability and for their approximate size. These characterized conjugated and non-conjugated GNPs were also analyzed by Transmission electron microscopy and Scanning electron microscopy. The GNP dot blot assay developed in this work gave promising results using vaccine antigen and can form an important tool for rapid diagnosis of FMD in FMD free countries, zones free of FMD and during last stage of FMD eradication when FMD vaccination will be withdrawn.

No abstract

In this study, serum samples from single vaccinated and multiple vaccinated animals, against Foot-and-mouth disease (FMD) were collected from field buffaloes. Samples with titre more than 1.4 in LPBE were selected for measuring antibody avidity. The study was conducted to compare the actual status of the protective antibody generated after vaccination in single and multiple vaccinated animals. The binding affinity of these antibodies were tested using an avidity ELISA. It was found that even after multiple vaccination in some of the animals the avidity was low whereas some of the single vaccinated animals showed high avidity than the multiple vaccinated animals. We conclude that multiple vaccination with strong antibody titre may not be always a true indicator of strong protective response. Hence, regular post-vaccination monitoring of antibody avidity needs to be done where there is a high virus circulation as a measure of herd immunity.

In endemic countries FMD outbreaks are controlled by vaccinating the animals by using a trivalent FMD vaccine. The aim of this study was to compare the avidity of antibodies developed against O and Asia 1 FMDV serotypes in multiple vaccinated animals against FMD. In this study, thirty-three serum samples from multiple vaccinated animals, against Foot-and-mouth disease (FMD) were collected from field buffaloes. Samples with titre more than 1.4 in LPBE were selected for measuring antibody avidity. The study was conducted to know the post vaccination avidity index of antibodies against O and Asia 1 serotype of FMDV. For this purpose, thirty three serum samples from multiple FMD vaccinated animals were tested by O and Asia 1 serotype specific indirect avidity ELISA.It was found that not all samples having high avidity antibodies for O serotype had high avidity antibodies for Asia 1 serotype.Similarly, not all samples having high avidity antibodies for Asia 1 serotype had high avidity antibodies for O serotype. However, no significant difference was observed in the mean avidity indices of antibodies for both O and Asia 1 serotype. As the avidity indices of antibodies may differ against different serotypes in an individual animal, hence, it is paramount to conduct regular post vaccination monitoring using avidity ELISA.