LSP1-/- DENDRITIC CELLS INDUCE DEFECTIVE ANTIGEN PRESENTATION TO CD4+ LYMPHOCYTES

NICOLAS DANIEL DHO; MERCEDES PASCUAL; MARÍA INÉS CRESPO; MARÍA C PISTORESI- PALENCIA; BELKYS A. MALETTO; G MORON

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Congreso; LXVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI); 2020

SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI)

Leukocyte-specific protein 1 (LSP1) is a 52 kDa cytoplasmic F-actinbinding phosphoprotein expressed in all human and murine leukocytesand endothelial cells. LSP1 is an important regulator of actincytoskeleton remodelling. We have previously shown that CD4+ Tcells from Lsp1-/- mice have a poorer proliferation than CD4+ T cellsfrom wild type (WT) mice after antigen exposure in vivo and in vitrowith bone marrow derived dendritic cells (BMDCs).In order to study the role of LSP1 in DCs to promote a CD4+ Tcell-mediated response, we evaluated the capacity of Lsp1-/- DCsto present antigens in a context of major histocompatibility complexclass II (MHC II). In vitro, BMDCs were derived from Lsp1-/- mice withFlt3-L. BMDCs were pulsed with soluble or particulated Ovalbumin(OVAw or OVAb, respectively), then stimulated with CpG-ODN 1826and finally cocultured with CD4+ T cells hybridoma (TH3Z OT II). Afteran overnight incubation, a significantly lower activation of TH3ZOT II cells was observed with Lsp1-/- BMDCs incubated with OVAw (p< 0.0001) and OVAb (p< 0.001) compared to Lsp1+/+ BMDCs.In addition, Lsp1-/- BMDCs show a lower expression of CD40, CD80,CD86 and MHC II molecules than BMDCs from WT mice after CpGODN1826 stimulus (p>0.05, p<0.05, p<0.0001, p<0.01 respectively).These results suggest that LSP1 deficiency affects DC antigen presentationmachinery in MHC II context.