LSP1 DEFICIENT MICE HAVE AN IMPAIRED CYTOTOXIC RESPONSE AFTER ANTIGEN EXPOSURE

RACHEL PAOLA ACLAND STRACK; ESTEFANÍA ZACCA; MERCEDES PASCUAL; MARÍA CRISTINA PISTORESI; BELKYS MALETTO; GABRIEL MORÓN

Buenos Aires

Congreso; LXIII reunion de la sociedad de inmunología; 2015

Abstract Text: Background: The leukocyte-specific protein 1 (LSP1), is a 52-kDa cytoplasmic F-actinbinding 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. Noinformation is available about the role of LSP1 in the triggering of immune response, particularly in thebiology of antigen presenting cells. We have previously reported that dendritic cells from Lsp1-/- micefail to induce a strong CTL response upon transfer to wild-type mice.Methods: Lsp1-/- and wild-typemice (B6 background) were subcutaneously immunized with OVA coupled to latex beads plus CpGODNas adjuvant into their footpads. Seven days later, popliteal lymph nodes (pLNs) were removed toevaluate T cell response. Results: the frequency and activation status of lymphoid and myeloid cellpopulations in pLNs of naïve Lsp1-/- vs wild-type mice are similar. After immunization, Lsp1-/- miceshow a poorer expansion of OVA-specific CD8+ T cells, as revealed by tetramer staining (p<0,01) aswell as lower CTL response (defined by CD107 expression) and IFNg intracellular staining on CD8+ Tcells (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-expressingmelanoma 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. Thisdeficiency could be related to an impaired activity of antigen presenting cells.