title: T-cell suppression and selective in vivo activation of TH2 subpopulation by the Entamoeba histolytica 220-kilodalton lectin.
abstract: A 220-kDa surface protein (L220) with lectin activity from Entamoeba histolytica trophozoites has been characterized previously (J. L. Rosales-Encina, I. Meza, A. López-de-León, P. Talamás-Rohana, and M. Rojkind, J. Infect. Dis. 156:790-797, 1987). This molecule is involved in the adhesion process (I. Meza, F. Cázares, J. L. Rosales-Encina, P. Talamás-Rohana, and M. Rojkind, J. Infect. Dis. 156:798-805, 1987) and is very immunogenic. In this work, we studied both the humoral and the cellular immune responses to L220. We compared L220 with L220-derived components, such as a fusion peptide (M-11) and chemically obtained peptides (by treating the 220-kDa molecule with N-chlorosuccinimide-urea). Spleen cells from L220-immunized mice were unable to proliferate in vitro when stimulated with the protein. However, a proliferative response was obtained when mice were immunized with the L220-derived fusion peptide or the cleaved lectin. To find out if there was a correlation between the observed responses and TH1 or TH2 activation, we analyzed patterns of cytokine secretion (interleukin-2 [IL-2], IL-4, IL-10, and gamma interferon). Cells from mice immunized with peptides that induced cell proliferation (100, 80, and 47 kDa) with the peptides (P < 0.01) and with the intact molecule secreted IL-2 and gamma interferon, showing a TH1-subset pattern. Conversely, cells from mice immunized with the intact 220-kDa molecule secreted IL-4 and IL-10, typical of a TH2 subpopulation; however, antibodies from each group recognized the 220-kDa molecule as determined by Western blotting (immunoblotting). These results suggest that various epitopes in the 220-kDa molecule generate different response patterns, suppressing or activating T-cell responses.
authors.affiliation: Department of Experimental Pathology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.
authors.forename: P
authors.initials: P
authors.lastname: Talamás-Rohana
authors.forename: M A
authors.initials: MA
authors.lastname: Schlie-Guzmán
authors.forename: V I
authors.initials: VI
authors.lastname: Hernández-Ramírez
authors.forename: J L
authors.initials: JL
authors.lastname: Rosales-Encina
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis; D004748:Entamoeba histolytica / Q000276:immunology*; D007114:Immunization; D037102:Lectins / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D015800:Protozoan Proteins / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D016207:Cytokines; D037102:Lectins; D015800:Protozoan Proteins