The Journal of Immunology, Vol 150, Issue 9 3951-3964, Copyright © 1993 by American Association of Immunologists

ARTICLES

Antibodies to Toxoplasma gondii major surface protein (SAG-1, P30) inhibit infection of host cells and are produced in murine intestine after peroral infection

JR Mineo, R McLeod, D Mack, J Smith, IA Khan, KH Ely and LH Kasper
Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire 03756.

Monoclonal and polyclonal, monospecific antibodies to the major surface antigen of Toxoplasma gondii (SAG-1, P30) inhibit infection of human fibroblasts and murine enterocytes. Fab prepared from polyclonal, monospecific antibody to P30 also have this inhibitory effect on invasion, which indicates that this antibody directly blocks parasite infection of host cells rather agglutinating the parasite. Antibodies to another surface protein (P22) did not alter in vitro infection. If the inhibitory effect of antibody to P30 was due to steric hindrance or complexing of surface epitopes contiguous to P30, antibodies to other surface epitopes would also be inhibitory and they are not. Urea treatment of antibody (which permits discrimination of high and low avidity antibody) did not alter the effect of anti-P30 antibody. This observation indicates that the effect of the antibody to P30 was not an artifact of differences in the avidity of the antibody to P22 and P30. Heat inactivated antisera from mice infected with either RH or PTg strain T. gondii (P30+) inhibit infection of fibroblasts when challenged with autologous wild-type parasites by 87 and 40%, respectively. In contrast, these antisera have little inhibitory effect (13 and 19%, respectively) against infection of human fibroblasts by a P30-deficient mutant (PTgB). Antisera raised to the P30-deficient mutant had no significant effect on infection of cells by wild-type strains that have surface P30. The neoglycoprotein, BSA-glucosamide, competitively blocks infection of human fibroblasts by P30+ tachyzoites with surface P30 in higher level than those without surface P30. This observation indicates that there is likely to be a glycosylated host cell receptor to which T. gondii's major surface Ag SAG-1 (P30) binds. Mice infected perorally develop intestinal IgA antibody to the major 30- kDa epitope of T. gondii. Thus, the major surface epitope of T. gondii, SAG-1 (P30), has an important, functional role in infection of host cells by T. gondii and elicits an intestinal antibody response after peroral infection.

This article has been cited by other articles:

				J. P. Gigley, B. A. Fox, and D. J. Bzik Long-Term Immunity to Lethal Acute or Chronic Type II Toxoplasma gondii Infection Is Effectively Induced in Genetically Susceptible C57BL/6 Mice by Immunization with an Attenuated Type I Vaccine Strain Infect. Immun., December 1, 2009; 77(12): 5380 - 5388. [Abstract] [Full Text] [PDF]

				D O Zamora, J T Rosenbaum, and J R Smith Invasion of human retinal vascular endothelial cells by Toxoplasma gondii tachyzoites Br J Ophthalmol, June 1, 2008; 92(6): 852 - 855. [Abstract] [Full Text] [PDF]

				A. Naguleswaran, A. M. Fialho, A. Chaudhari, C. S. Hong, A. M. Chakrabarty, and W. J. Sullivan Jr. Azurin-Like Protein Blocks Invasion of Toxoplasma gondii through Potential Interactions with Parasite Surface Antigen SAG1 Antimicrob. Agents Chemother., February 1, 2008; 52(2): 402 - 408. [Abstract] [Full Text] [PDF]

				E. Charles, M. C. Callegan, and I. J. Blader The SAG1 Toxoplasma gondii Surface Protein Is Not Required for Acute Ocular Toxoplasmosis in Mice Infect. Immun., April 1, 2007; 75(4): 2079 - 2083. [Abstract] [Full Text] [PDF]

				K. N. Couper, C. W. Roberts, F. Brombacher, J. Alexander, and L. L. Johnson Toxoplasma gondii-Specific Immunoglobulin M Limits Parasite Dissemination by Preventing Host Cell Invasion Infect. Immun., December 1, 2005; 73(12): 8060 - 8068. [Abstract] [Full Text] [PDF]

				J. Mital, M. Meissner, D. Soldati, and G. E. Ward Conditional Expression of Toxoplasma gondii Apical Membrane Antigen-1 (TgAMA1) Demonstrates That TgAMA1 Plays a Critical Role in Host Cell Invasion Mol. Biol. Cell, September 1, 2005; 16(9): 4341 - 4349. [Abstract] [Full Text] [PDF]

				F. Lu, S. Huang, M. S. Hu, and L. H. Kasper Experimental Ocular Toxoplasmosis in Genetically Susceptible and Resistant Mice Infect. Immun., August 1, 2005; 73(8): 5160 - 5165. [Abstract] [Full Text] [PDF]

				D. K. Howe, R. Y. Gaji, M. Mroz-Barrett, M.-J. Gubbels, B. Striepen, and S. Stamper Sarcocystis neurona Merozoites Express a Family of Immunogenic Surface Antigens That Are Orthologues of the Toxoplasma gondii Surface Antigens (SAGs) and SAG-Related Sequences Infect. Immun., February 1, 2005; 73(2): 1023 - 1033. [Abstract] [Full Text] [PDF]

				V. Letscher-Bru, A. W. Pfaff, A. Abou-Bacar, D. Filisetti, E. Antoni, O. Villard, J.-P. Klein, and E. Candolfi Vaccination with Toxoplasma gondii SAG-1 Protein Is Protective against Congenital Toxoplasmosis in BALB/c Mice but Not in CBA/J Mice Infect. Immun., November 1, 2003; 71(11): 6615 - 6619. [Abstract] [Full Text] [PDF]

				E. V. Lourenco, S. R. Pereira, V. M. Faca, A. A. M. Coelho-Castelo, J. R. Mineo, M.-C. Roque-Barreira, L. J. Greene, and A. Panunto-Castelo Toxoplasma gondii micronemal protein MIC1 is a lactose-binding lectin Glycobiology, July 1, 2001; 11(7): 541 - 547. [Abstract] [Full Text] [PDF]

				C. Bonenfant, I. Dimier-Poisson, F. Velge-Roussel, D. Buzoni-Gatel, G. Del Giudice, R. Rappuoli, and D. Bout Intranasal Immunization with SAG1 and Nontoxic Mutant Heat-Labile Enterotoxins Protects Mice against Toxoplasma gondii Infect. Immun., March 1, 2001; 69(3): 1605 - 1612. [Abstract] [Full Text] [PDF]

				M. W. Black and J. C. Boothroyd Lytic Cycle of Toxoplasma gondii Microbiol. Mol. Biol. Rev., September 1, 2000; 64(3): 607 - 623. [Abstract] [Full Text] [PDF]

				P. C. Sayles, G. W. Gibson, and L. L. Johnson B Cells Are Essential for Vaccination-Induced Resistance to Virulent Toxoplasma gondii Infect. Immun., March 1, 2000; 68(3): 1026 - 1033. [Abstract] [Full Text] [PDF]

				J. Y. Channon, E. I. Suh, R. M. Seguin, and L. H. Kasper Attachment Ligands of Viable Toxoplasma gondii Induce Soluble Immunosuppressive Factors in Human Monocytes Infect. Immun., May 1, 1999; 67(5): 2547 - 2551. [Abstract] [Full Text] [PDF]

				E. Ortega-Barria and J. C. Boothroyd A Toxoplasma Lectin-like Activity Specific for Sulfated Polysaccharides Is Involved in Host Cell Infection J. Biol. Chem., January 15, 1999; 274(3): 1267 - 1276. [Abstract] [Full Text] [PDF]

				D. K. Howe, A. C. Crawford, D. Lindsay, and L. D. Sibley The p29 and p35 Immunodominant Antigens of Neospora caninum Tachyzoites Are Homologous to the Family of Surface Antigens of Toxoplasma gondii Infect. Immun., November 1, 1998; 66(11): 5322 - 5328. [Abstract] [Full Text] [PDF]

				I. Bourguin, M. Moser, D. Buzoni-Gatel, F. Tielemans, D. Bout, J. Urbain, and O. Leo Murine Dendritic Cells Pulsed In Vitro with Toxoplasma gondii Antigens Induce Protective Immunity In Vivo Infect. Immun., October 1, 1998; 66(10): 4867 - 4874. [Abstract] [Full Text] [PDF]

				F. T. Liang, D. E. Granstrom, X. M. Zhao, and J. F. Timoney Evidence that Surface Proteins Sn14 and Sn16 of Sarcocystis neurona Merozoites Are Involved in Infection and Immunity Infect. Immun., May 1, 1998; 66(5): 1834 - 1838. [Abstract] [Full Text] [PDF]

				I. D. Manger, A. B. Hehl, and J. C. Boothroyd The Surface of Toxoplasma Tachyzoites Is Dominated by a Family of Glycosylphosphatidylinositol-Anchored Antigens Related to SAG1 Infect. Immun., May 1, 1998; 66(5): 2237 - 2244. [Abstract] [Full Text] [PDF]

				F Seeber, J. Dubremetz, and J. Boothroyd Analysis of Toxoplasma gondii stably transfected with a transmembrane variant of its major surface protein, SAG1 J. Cell Sci., January 1, 1998; 111(1): 23 - 29. [Abstract] [PDF]

				K Kim, D Soldati, and J. Boothroyd Gene replacement in Toxoplasma gondii with chloramphenicol acetyltransferase as selectable marker Science, November 5, 1993; 262(5135): 911 - 914. [Abstract] [PDF]

				S. Brecht, V. B. Carruthers, D. J. P. Ferguson, O. K. Giddings, G. Wang, U. Jakle, J. M. Harper, L. D. Sibley, and D. Soldati The Toxoplasma Micronemal Protein MIC4 Is an Adhesin Composed of Six Conserved Apple Domains J. Biol. Chem., February 2, 2001; 276(6): 4119 - 4127. [Abstract] [Full Text] [PDF]