Functional effects of antibodies against non-neuronal nicotinic acetylcholine receptors

Non-neuronal nicotinic acetylcholine receptors (nAChRs) are expressed in the spleen and regulate B lymphocyte propagation and activation. The aim of the present study was to investigate the cellular and physiological effects of antibodies against α4(1–209) and α7(1–208) nAChR extracellular domains. The antibodies, added in vitro, produced in vivo or injected, specifically bound mouse spleen B lymphocytes. Immunization with nAChR extracellular domains resulted in connective tissue overgrowth and infiltration of segmented neutrophils in the spleen, as well as in decreased body weight compared to mice immunized with BSA. In spite of certain cross-reactivity of α4(1–209)- and α7(1–208)-specific antibodies, all observed effects were more pronounced upon immunization with α7 extracellular domain. Spleens of mice injected with α7(1–208)-specific antibody contained decreased numbers of Annexin V-positive B lymphocytes compared to mice injected with non-specific IgG. It is concluded that α7 nAChRs are involved in regulating the lymphocyte survival, neutrophil migration, connective tissue overgrowth and body weight accumulation. The antibody binding triggers α7 nAChR signaling supporting the idea of non-channel mode of nAChR functioning in B lymphocytes.