Cryptococcosis:Immunopathological study in mice immunized with Cryptococcus neoforman antigens

The aims of the present study were used the culture filtrate Cryptococcus neoforman (Cncf) antigens for immunization of mice against Cryptococcal infection and compare it with the whole killed Cryptococcal cell (WkCc) Ag.70 whit Swiss BALB/C mice from both sexes were used, and divided into four groups: 1. First group (20 mice) was immunized twicely with 0.2 ml from Cryptococcus neoformans culture filtrate (Cncf) Ag contained 10.6 mg of protein intrapretonialy (I/P) with two weeks interval. 2. Second group (20 mice) was immunized twicely with 0.2 ml from the Whole killed Cryptococcal cells (WkCc) Ag containing 6.3×108 cells/ml I/P with two weeks interval.3. Third group (10 mice) was considered as a control positive. After 30 days, first,c second and 3rd groups was infected by challenge dose of virulence C.neoformans strain, 0.5 ml I/P with 1.5×107 cells/ml. 4. Fourth group (10 mice) was inoculated by 0.5 ml phosphate buffer saline as a control negative. At 27 days post-immunization of first and second groups estimation of cellular immune response, was done by skin test and humeral immune response by passive haemagglutination test. After 30 days, 1st, 2nd and 3rd group was infected by challenge dose of virulence C. neoformans strain, 0.5 ml/ P with 1.5 ×107 cells/ ml. And after 30 and 60 days post-infection, 5 mice from each groups were also sacrificed for fungal isolation and the histopathological change was study. The result showed that Cncf Ag elicited high Ab titer, good cellular immune response, no clinical signs, negative fungal isolation and hyperplasia of lymphoid tissue against Cryptococcal infection in the first group as compare with the second group that immunized by WkCc Ag and the control group, while non-immuize –infeced animals showed heavy fungal solation with severe pathological changes including granulomatous lesion, amyloid deposition and cell destruction and necrosis in the internal organs.