This is a family of 15kDa salivary proteins from Acari Arachnids that is induced on feeding and assists the parasite to remain attached to its arthropod host. By repressing calcium fluxes triggered by TCR engagement, Salp15 inhibits CD4+ T cell activation. Salp15 shows weak similarity to Inhibin A, a member of the TGF-beta superfamily that inhibits the production of cytokines and the proliferation of T cells.

1: Salp15, an ixodes scapularis salivary protein, inhibits CD4(+) T cell activation. Anguita J, Ramamoorthi N, Hovius JW, Das S, Thomas V, Persinski R, Conze D, Askenase PW, Rincon M, Kantor FS, Fikrig E; Immunity. 2002;16:849-859. PMID:12121666