LSP1 DEFICIENT MICE HAVE AN IMPAIRED CYTOTOXIC RESPONSE AFTER ANTIGEN EXPOSURE.

RACHEL ACLAND; ESTEFANÍA ZACCA; MERCEDES PASCUAL; MARÍA C PISTORESI- PALENCIA; BELKYS A. MALETTO; G. MORON

Buenos Aires

Congreso; 2nd French-Argentine Immunology Congress y LXIII Reunión de la Sociedad Argentina de Inmunología.; 2015

Sociedad Argentina de Inmunología

The leukocyte-specific protein 1 (LSP1), is a 52-kDa cytoplasmic F-actin binding phosphoprotein expressed in all human and murine leukocytes as well as in endothelial cells. LSP1 is an important regulator of actin cytoskeleton remodeling, modulating neutrophil motility. No information is available about the role of LSP1 in the triggering of immune response, particularly in the biology of antigen presenting cells. We have previously reported that dendritic cells from Lsp1-/- mice fail to induce a strong CTL response upon transfer to wild-type mice. Methods: Lsp1-/- and wild-type mice (B6 background) were subcutaneously immunized with OVA coupled to latex beads plus CpG-ODN as adjuvant into their footpads. Seven days later, popliteal lymph nodes (pLNs) were removed to evaluate T cell response. Results: the frequency and activation status of lymphoid and myeloid cell populations in pLNs of naïve Lsp1-/- vs wild-type mice are similar. After immunization, Lsp1-/- mice show a poorer expansion of OVA-specific CD8+ T cells, as revealed by tetramer staining (p<0,01) as well as lower CTL response (defined by CD107 expression) and IFNg intracellular staining on CD8+ T cells (p<0,05). However the frequency of effector and memory CD8+ T cells (determined by CD44, CD62L and CD25) are similar between both Lsp1-/- and wild-type mice. Finally, OVA-expressing melanoma tumor cells (MO5 cells) have a higher growth rate in Lsp1-/- than in wild-type mice. Conclusions: Lsp1-/- mice had a lower capacity to generate a CTL response than wild-type mice. This deficiency could be related to an impaired activity of antigen presenting cells.