Dynamics of CD62L/CD45RB CD4+ and CD8+ lymphocyte subsets in hepatic and splenic tissues during murine visceral leishmaniasis

This study aimed to characterise, for the first time, the dynamics of CD4⁺ and CD8⁺ lymphocyte CD62L/CD45RB subsets, during visceral leishmaniasis. Memory/activated status of hepatic and splenic T cells was compared in mice strains with "cure" and "non-cure" phenotypes to Leishmania infantum infection. In both mice strains, a correlation between the dynamics of the memory CD4⁺ and CD8⁺ T cells (CD62L^low/CD45RB^low) subsets in the liver and the pre-activated phenotype of lymphocytes (CD62L^low/CD45RB ^high) from the spleen was detected suggesting that this organ is the source of Leishmania-specific T lymphocytes that migrate to the liver, where parasite replication is highly active. In the liver, these pre-activated cells become effector T lymphocytes, however, a strong regulation of CD8⁺ T cell effector function was observed, probably preventing hepatic tissue damage. Comparing mice strains with "cure" and "non-cure" phenotype, an imbalance between "protective" CD45RB^high and "pathogenic" CD45RB^low CD4⁺ subsets in B10.D2/n animals might be involved in the evolution of a non-healing infection.