Inflammatory immune response elicited by the cross-interaction between trophoblasts, monocytes and neutrophils infected with Brucella abortus

FERNANDEZ, AG; FERRERO, MARIANA; HIELPOS, MS; FOSSATI , CARLOS ALBERTO; BALDI, PABLO CESAR

Mar del Plata

Congreso; LXII REUNIÓN ANUAL Sociedad Argentina de Inmunología; 2014

Sociedad Argentina de Inmunología

It is well known that Brucella induces abortion in humans and animals, very likely due to a shift towards an inflammatory profile of cytokines present at the maternal-fetal interface. In this work we evaluated cytokines and chemokines secreted after the interaction of human trophoblasts, monocytes and neutrophils infected with B. abortus. The trophoblastic cell line Swan-71 (Sw71), the monocytic cell line THP1, and neutrophils isolated from peripheral blood were infected with B. abortus 2308 at a multiplicity of infection of 100 for 2 h. After treatment with gentamicin, supernatants were collected at 24 or 48 h post  infection and filter-sterilized. THP1 and neutrophils were stimulated with conditioned medium (CM) from infected Sw71 cells. An increase in IL-8 (p<0,05) and IL-6 (p<0,001) levels was detected after stimulation only in THP-1 cells. In a reciprocal experiment, when Sw71 cells were stimulated with CM from infected monocytes (CM-m) or neutrophils (CM-n), an increase in MCP1, IL8 and IL6 was observed (p<0,001 to p<0,05 in all cases). To analyze the possible involvement of TNF alpha and IL1beta in these stimulations, two series of experiments were performed. First, we confirmed that trophoblastic cells respond to recombinant human TNF alpha and IL1beta with an increased production of IL8 and MCP1 (p<0,001 at all concentrations tested). Second, CM-m and CM-n were treated with a  neutralizing anti-human TNF antibody or recombinant human IL1ra (IL1 receptor antagonist) before using them to stimulate Sw71 cells. IL1ra produced a significant decrease in the secretion of IL8 and IL6 in response to both CM (p<0,05), whereas both blocking agents decreased MCP1 production in response to CM-n (p<0,05). These findings show that cross-interaction between trophoblasts and immune cells during B. abortus infection lead to an inflammatory cytokine profile which might be involved in fetus miscarriage.