Modification of antibody specificity by cytokines inhibition

MACARENA A. OTTOBRE SABORIDO; JOSÉ L. APARICIO

Congreso; IV International Congress in Translational Medicine; 2018

Introduction: Lactate Dehydrogenase Elevating Virus (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.Objectives: The purpose of this work was to study, through of anti-cytokine auto-vaccination and monoclonal antibody (MAb) treatment, the effect in the change of specificity of antibodies to an model antigen (OVA). Methods: i) C57BL/6 mice were infected with 2×107 50% infectious doses of LDV in saline. Subsequently, the animals were inoculated in the footpads, four times at 2-wk intervals, with 2μg of IL-17/OVA complex emulsified in Gerbu adjuvant. Ten days after the last inoculation the animals were bled. ii) C57BL/6 mice 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 were inoculated intraperitoneally with 150 µg of anti-IL-17A MAb (MM17F3) in 200 µl of PBS. Another mouse group were treated as before but infected with 2×107 50% infectious doses of LDV in saline at day -1. Bleeding was performed at days 8, 21, and 30. IL-17 concentration was measured by Sandwich ELISA. The titer of Ab anti-OVA was determinated by Indirect ELISA whereas the proportion of Ab directed to native OVA epitopes was calculated by ELISA competition assays.Results: Vaccination with IL-17/OVA decreased titers of anti-OVA Ab LDV-infected (1/290,000 ± 6,000) and non-infected animals (1/280,000 ± 17,000), respect to control mince only inoculated with OVA (790,000 ± 70,000, P