Disease Susceptibility and Cytokine Production in F1 Generation of Mice Cross Breed of Swiss Albino with BALB/c Mice (SAB) following Leishmania donovani Infection

The difference between Swiss albino (resistant) and BALB/c (susceptible) strains in response to L. donovani infection has been linked to inheritable genes, and the GATAq and Lsh group of genes plays a key role in disease transmission. This study sought to investigate effects of gene neutralization through cross breeding and back crossing. SAB mice were generated by cross breeding of BALB/c mice and Swiss Albino mice. This study aimed at investigating the susceptibility, immune response and pathology of SAB mice after L. donovani infection. Serum was collected from all mice groups 4 weeks post infection and levels of IFN-γ and IL-4 cytokine were determined using ELISA. Body and spleen weights were measured, and tissue section stained for histopathology examination. In this study the L. donovani infected swiss mice had significantly low amounts of IL-4 as compared to the SAB mice (P=0.0093). Whereas the IL-4 levels in BALB/c mice were not significantly different to that of SAB mice (P= 0.1507). Conversely infected swiss albino mice had significantly high amounts of IFN-γ compared to SAB (P=0.0216) and BALB/c (P=0.0326) mice. No significant difference in IFN-γ levels were between the groups. No significant difference in body and splenic weights between groups (P>0.05). Pathologically there was observed proliferation of kupffer cells, degenerated hepatocytes and fibrosis in BALB/c and SAB mice. In addition, there was chronic degeneration of structure of spleen of SAB mice characterized by disruption, an indication of severe infection. Results obtained in this study show that SAB mice can be used in studies involving L. donovani parasites. This mouse model can be used in the absence of BALB/c mice owing to their susceptibility to L. donovani. Further studies are needed to be carried out to determine other factors e.g genetic makeup that makes it susceptible to L. donovani parasites. 

Keywords: SAB Mice, Leishmaniasis, Hepatocytes, Fibrosis, Histopathology Examination.