Anti IL-17A treatment in mice infected with Lactate Dehydrogenase Elevating Virus (LDV) change the titer and isotypes profile of specific antibodies

MACARENA A. OTTOBRE SABORIDO; JOSÉ L. APARICIO

Jornada; VIII JORNADAS DE JÓVENES INVESTIGADORES; 2018

LDV is a single stranded positive sense RNA enveloped arterivirus, is persistent, non pathogenic and induces NK, macrophages and B- cell activation in mice. It was found that LDV- infection modified Ab specificity to different antigens, depending on the genetic background of the host. This effect was correlated with the release of diverse cytokines after viral infection recently. Recently, we have shown that inhibition of a pro-inflammatory cytokine, interleukin 17A (IL-17A) induce a modification in the specificity of antibodies against conformational epitopes to a given antigen. The purpose of this work was to study, through of monoclonal antibody (MAb) treatment, the relation between the change of specificity in antibodies to an antigen such as, ovalbumin (OVA) and the variation in the immunoglobulin isotype profile. C57BL/6 mice (n = 18) were inoculated subcutaneously with 25 μg of OVA emulsified in phosphate-buffered saline (PBS) and Complete Freund?s Adjuvant. At day 15, the mice were boosted with the Ag in Incomplete Freund?s Adjuvant. At days 4, 7 and 11, half of the animals (n = 9) were inoculated intraperitoneally with 150 µg of MAb anti-IL-17A (MM17F3) in 200 µl of PBS. A group of mice (n = 9) were treated as before but infected with 2×107 50% infectious doses of LDV in saline solution at day 0. As control, a group of mice (n = 5) were only infected with LDV and another group (n=4) without treatment. Bleeding was performed at days 8, 21, and 32. The titer of Ab anti-OVA was determined by Indirect ELISA, whereas the proportion of Ab directed to native OVA epitopes was calculated by ELISA competition assays. The immunoglobulin isotypes (IgM, IgG1, IgG2a and IgG2b) were measured by Sandwich ELISA. Titers of anti-OVA Ab in LDV-infected animals decreased by MAb MM17F3 treatment (1/167000 ± 1/12600 to 1/68000 ± 1/4700, for control and MAb treated mice, respectively, P