title: P3 mAb: An Immunogenic Anti-NeuGcGM3 Antibody with Unusual Immunoregulatory Properties.
abstract: P3 is a murine IgM mAb that recognize N-glycosylated gangliosides, sulfatides, and antigens expressed in melanoma, breast, and lung human tumors. This antibody has the ability to trigger an IgG antibody response in the syngeneic BALB/c model, even when it is administered in the absence of adjuvant or carrier protein. The mechanism by which the P3 mAb, a self-immunoglobulin, induce this immune response in the absence of co-stimulatory or classical danger signals is still unknown. In the present paper we show that the high immunogenicity of P3 mAb depends not only on CD4 but also on CD8(+) T cells, since the depletion of CD8(+) or CD4(+) T cells led to the loss of P3 mAb immunogenicity in the syngeneic model. Furthermore, the immunization with P3 mAb enhanced the recovery of the CD8(+) T cell population in mice treated with an anti-CD8a antibody. Additionally, the immunization with P3 mAb restored the capacity of immunosuppressed mice to reject allogeneic tumors, a mechanism mediated by the action of CD8(+) T cells. Finally, in mice with cyclophosphamide induced lymphopenia, the administration of P3 mAb accelerated the recovery of both CD4(+) and CD8(+) T cells. These results show new possibilities for B and CD8(+) T cells interactions during the immune response elicited by a self-protein. Furthermore they point to P3 mAb as a potential interesting candidate for the treatment of immunosuppressed patients.
authors.affiliation: Tumor Immunology Direction, Center of Molecular Immunology Havana, Cuba.
authors.forename: Darel
authors.initials: D
authors.lastname: Martínez
authors.forename: Nely
authors.initials: N
authors.lastname: Rodríguez
authors.forename: Tania
authors.initials: T
authors.lastname: Griñán
authors.forename: Teresa
authors.initials: T
authors.lastname: Rondón
authors.forename: Ana María
authors.initials: AM
authors.lastname: Vázquez
authors.forename: Rolando
authors.initials: R
authors.lastname: Pérez
authors.forename: Ana María
authors.initials: AM
authors.lastname: Hernández