6 research outputs found
The immune response of the teleost, Tilapia mossambica to soluble and cellular antigens
The immune response of Tilapia mossambica to bovine serum albumin (BSA) and sheep red blood cells (SRBC) was characterized in detail in terms of the appearance of hemolysin plaque-forming cells and circulating antibodies at 30°C. Plaque-forming cells (PFC) were detected in the spleen, head-kidney and thymus of immunized fish and the maximum number was observed in these organs on the fifth day after immunization with SRBC. Peak circulating antibody response occurred on day 8 for SRBC and on day 11 for BSA. Following the second injection of the same antigen, a specific anamnestic response was observed with increased production of PFC and serum antibody. No cross reactivity was found when anti-SRBC antibody was tested with rat erythrocytes. Tests with 2-mercaptoethanol showed that all of the agglutinating antibody produced after both the first and second injection was mercaptoethanol sensitive. Analysis of histological and smear preparations revealed that there were consistent cellular changes occurring in the spleen as well as the head-kidney due to immunization
Morphology of lymphoid organs in a cichlid teleost, Tilapia mossambica (Peters)
In Tilapia mossambica organized lymphoid tissues are present in the thymus, head-kidney and spleen, whereas they are lacking in pericardial tissue, liver, mesonephros, intestine and rectum. No lymphoid tissue was observed in the chondrocranium and cartilaginous viscerocranium of young adults. The thymus in Tilapia is encapsulated by thin strands of collagen fibers and consists of outer, middle and inner zones. While middle and inner zones are comparable to the thymic cortex and medulla of higher vertebrates, the homology of the outer zone is not clear. At the anterior end of the thymus, a loose aggregation of lymphocytes without a definite boundary has been observed. The head-kidney is characterized by the presence of lymphoid follicles, a subcapsular sinus, a hilus-like area and lymphatic vessels. The spleen is grossly divisible into white pulp and red pulp; the white pulp contains only a reticular area without definite lymphoid centers and the latter contains predominantly erythrocytes. Morphological changes in the lymphoid organs associated with immune response have been discussed