ABSENCE OF LEUKOCYTE SPECIFIC PROTEIN 1 (LSP1) ALTER ACTIVATION AND PROLIFERATION OF CD4+ AND CD8+ T LYMPHOCYTES

LOPEZ MENICHETTI, GUADALUPE ANAHÍ; PASCUAL, MARÍA MERCEDES; RUIZ MORENO, FEDERICO; CRESPO, MARÍA INÉS; MALETTO, BELKYS A; MORÓN, GABRIEL; DHO, NICOLÁS DANIEL

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias SAIC-SAI&FAIC-SAFIS; 2022

Sociedad Argentina de Inmunología

Leukocyte-specific protein 1 (LSP1) is a 52 kDa cytoplasmic F-actin binding phosphoprotein expressed in all human and murine leukocytes and endothelial cells. We have previously shown that Lsp1-/- mice have an impaired CTL response after antigen exposure, with Lsp1-/- dendritic cells (DCs) failing to induce a strong CTL response in vivo and a lower CD4+ T cell-mediated response.In order to study the role of LSP1 in T cell functionality, we evaluated the capacity of Lsp1-/- CD4+ and CD8+ T lymphocytes to activate and proliferate in vitro. T cells were purified from spleen of Lsp1-/- and WT mice by cell sorter after labeling splenocytes with anti-CD8β (to purify T CD8+ cells), anti-CD11b and anti-CD4 antibodies to purify T CD4+ lymphocytes. Sorted T cells were then stained with eF670 proliferation dye and finally cocultured with Ab anti-CD28 in a well plate sensitized with anti-CD3. Three days later, a significantly lower percentage of activated cells expressing CD69 (p<0.001) or CD44 (p<0.0001) was observed in Lsp1-/- CD4+ T Lymphocytes and inside the activated cells gate, the proliferating percentages was lower too in Lsp1-/- CD4+ T Lymphocytes (p<0.01 and p<0.0001 respectively). Something similar was seen in Lsp1-/- CD8+ T Lymphocytes, with a significantly lower percentage of proliferating cells (p<0.01) and CD44 expression (p<0.001) than their WT counterpart cells. To assess the lymphocytes activity in the previous assay, we measure IL-2, IL-17, TNF and IFNᵧ in supernatant by sandwich ELISA. We found that in Lsp1-/- CD4+ T Lymphocytes produced less IL-2 and IFNᵧ (p<0.05 and not quantifiable for WT respectively) and significantly more IL-17 (p<0.05) than WT CD4+ T cells. Lsp1-/- CD8+ T Lymphocytes produced significant less TNF (p<0.001) and, in contrast to WT CD8+ T cells, not measurable IL-2.These results suggest that LSP1 deficiency also affects T cell activation and proliferation, which could impair induction of effector responses in mice.