Immunoglobulin producing cells in chickens immunized with Eimeria tenella gametocyte antigen vaccines

The present paper reports on the IgA, IgG and IgM antibodies secreting cells (ASC) in the spleen of chickens vaccinated with E. tenella (local isolates) gametocyte vaccine(s) by using Enzyme Linked Immunospot (ELISPOT) assay. Irrespective of the vaccine used, the number of IgG antibody secreting cells (ASC) in the spleen of orally vaccinated chickens was higher than the number of IgA and IgM ASC. Maximum numbers of IgG, IgA and IgM ASC were found in chickens vaccinated with sonicated gametocyte formalin inactivated vaccine (Group III) followed by formalin inactivated gametocytes (Group II) and gametocytes (Group I). The number of ASC (IgG, IgA and IgM) per 104 cells in spleen was significantly higher (P < 0.05) in Group III as compared to Group II and Group I. Results of the challenge experiments revealed maximum protection against mixed species of the genus Eimeria in Group III (77.8%) followed by Group II (55.6%) and Group I (52.0%). Lesion scoring was directly proportional to the per cent mortality and oocysts per gram of droppings but inversely proportional to the per cent protection. Based on the results, it was assumed that the spleen in chickens is one of the major sources of cells producing IgA, IgG and IgM antibodies.