The effect of immunizing laboratory rabbits infected with Giardia lamblia with antigen (O) purified from Escherichia coli on some immunological parameters

Abstract

Abs

This study was take placed for the period from December 2021 until January 2022, and it included a follow-up of the effect of Outer Membrane Proteins (OMPs) or the so-called (O-antigen) purified from Escherichia coli bacteria on the immune response in (45) male laboratory white rabbits, 15 of them infected with Giardia lamblia and others did not provoke infection, but were treated with O-antigen only. The immune response was studied based on several criteria including changes in phagocytic index, viability of polymorphonuclear cells (PMNs) and Lymphocytes, active and total of T-rosette and B-rosett. The present results showed that the percentage of viability of lymphocytes and PMNs significantly increased for the antigen-treated group compared with the negative control, but in challenge group, it was noted that the viability of lymphocytes and PMNs cells was not affected by the presence of the parasite and remained high. As the current study showed, the phagocytic index was significantly increased in the two groups (treated with O-antigen, and challenge group) compared with the negative control group, as there was a non-significant decrease in challenge group compared with treated with O-antigen group. The results of the current study showed that there were statistical differences in the group of animals treated with O-antigen compared with the negative control, which were not significant for the active T-rosette,and significant for the total T-rosette, and as our current results showed, the percentage of active T-rosette significantly increased in challenge group compared with the positive control, and not significant in the case of the total T-rosette. We conclude from the current study the percentage increased of each of the phagocytic index, T-rosette and B-rosette after immunization with antigen (O), as well as the percentage of viability of lymphocytes and PMNs cells after immunization with antigen (O) and their persistence in the presence of G. lamblia. The outer membrane proteins extracted from E. coli and the concentrations used in the current study can be considered as non-specific immunomodulators and non-toxic compounds at the specified concentrations and as stimulators of the immune system against G. lamblia infection in white laboratory rabbits.