The possibility of rat re-infection with different Toxoplasma
gondii stages was studied in this work. Two groups of rats were
infected with either intra-peritoneal injection of 1000
trophozoites of virulent Toxoplasma strain or 1000 oocysts
.through oral routes. IgA, IgM and 1gG were detected 15, 30, 60
and 120 days post infections. IgA and 1gM appeared as early as
15 days post infection but declined after wards. IgA antibody
response was more prominent with oocyst infection and IgM
was more prominent with tachyzoites infection with insignificant
statistical difference. On the other hand, IgG started to increase.
60 days post infection, then increased gradually till the end of
the experiment (120 days). The primary orally infected rats were
either re-infected orally with oocysts or intra-peritoneal
trophozoites and re-examined after 15 and 120 days for the
same immunological parameters. Those rats which primary
infected with intra-peritoneal trophozoites were re-examined
after oral infection with oocysts or injection of trophozoites intraperitoneal.
The level of IgA and IgM in one rat of group A and 2
rats of group B are significantly increased and this occurred in
presence of anti-Toxoplasma IgG from the primary infection. In
this study, the rats were lab-bred so, the factors affect the
immune system could be under control, also strain variability
It
1•11,10.11411.11.1114•• •
was excluded as the infection was by only one strain, and as
the IgG level was high, these rats were presumed to be immune
from the primary infection. So the rats which became positive
after challenge most probably re-infected. |
