Differential Protease Activity in the Secondary Lymphoid Tissues of Disease Resistant and Susceptible Mouse Strains in the MAIDS Model (45.12)

Abstract

Abstract Murine leukemia virus (MuLV) is used as a mouse model system to study human AIDS. There are two strains of mice used in this model, BALB/c and C57 BL/6. Although both strains of mice will become infected, BALB/c strain recover while the BL/6 strain becomes immunocompromised (MAIDS). Previous DNA microarray work comparing the two strains has shown that certain proteases are up regulated in the BALB/c lymph nodes and spleen shortly after infection. Lymphatic remolding and cell activation are possible consequences of protease activity, and therefore the up regulation of these proteases in the BALB/c strain may be important for recovery. Using immunofluoresent microscopy and in situ zymography, quantification of protease activity in the lymph nodes of each strain was studied in the first days after MuLV infection. Serial sections were stained for lymphatic (LYVE-1) and vascular (CD31) endothelial structures using primary and fluorescently-conjugated secondary antibodies. This was combined with protease-mediated activation of quenched substrate fluorphores (in situ zymography) allowing co-localization of protease activity and lymphatic morphology. Preliminary in situ zymography results show that there is an increase in protease activity in BALB/c mice when compared to BL/6 in the lymph nodes. Furthermore, preliminary immunofluorescent results show an increase in the vascular and lymphatic branching within the BALB/c lymph nodes following MuLV infection.