Reactivity Of Immune Sera Research Articles

Immunohistological localization of autoantigens detected by serum autoantibodies from mice with experimental autoimmune orchitis without using adjuvants.

Recently, a murine model of testicular autoimmunity was produced in mice by subcutaneous injections with viable syngeneic testicular germ cells alone, without depending on the use of any adjuvants or immunopotentiators. In this article, histological localization of autoantigens detected by circulating autoantibodies was immunohistochemically studied by reacting the immune sera with frozen sections of testes from mice of various ages. The study showed that the reactivity of immune sera was detected in the testis sections of normal mice older than 24 days of age but not in those of mice younger than 20 days of age. The immunostain was detected at proacrosomal, acrosomal, and other cytoplasmic regions of variously shaped developing spermatids but never on pachytene spermatocytes, basal compartment germ cells, or the supporting tissue of the seminiferous tubules.

Induction of protective immunity by using Anaplasma marginale initial body membranes

Anaplasma marginale initial bodies of the Norton Zimbabwe strain were disrupted and separated into two membrane fractions banding at 1.15 and 1.22 g/cm3 by sucrose density centrifugation. The membrane fractions differed in their morphology and polypeptide composition. Membranes banding at 1.22 g/cm3 shared epitopes with surface-exposed polypeptides of the Florida strain of A. marginale, confirming the outer membrane location of these polypeptides. Immunization of cattle with either membrane fraction induced protection against homologous challenge, as demonstrated by significantly less anemia and lower peak rickettsemia values compared with those of adjuvant-immunized and nonimmunized calves. Protection correlated with antibody titer to membrane polypeptides. Although both membrane fractions induced protection, a 31-kDa polypeptide was the only common antigen to both fractions, as shown by reactivity of immune sera. Identification of membrane antigens capable of inducing protective immunity should facilitate development of vaccines against anaplasmosis suitable for use in Zimbabwe.

Multiple antigen peptides for specific detection of antibodies to a malaria antigen in human sera

Multiple antigen peptides (MAP), consisting of a number of peptide copies synthesized on a branching lysyl core, offer a novel approach for rendering small peptides immunoreactive in solid-phase immunoassays. An octameric MAP, carrying 6 repeats of the sequence -N-A-A-G-, tandem repeated in the immunodominant region of the circumsporozoite (CS) protein of Plasmodium malariae, was used as a model to evaluate the suitability of the MAP system in an indirect enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against a parasite antigen in individuals exposed to natural infection. The reaction of endemic sera in ELISA on MAP8-(NAAG)6 was related to that obtained in immunofluorescence on sporozoites, indicating the specificity of the antibody-MAP interaction. The reactivity of immune sera was found to be directed only against the (NAAG)6 moiety of the MAP and not against the lysyl core, since antibody binding to MAP8-(NAAG)6 was completely inhibited by (NAAG)6-NA monomer, but remained uninfluenced when lysyl core was used as competing ligand. The levels of antibodies to MAP8-(NAAG)6, in two groups of individuals naturally exposed to malaria infection, appeared to be related to their respective exposure to the parasite.

Diversity of Antigens Expressed on the Surface of Erythrocytes Infected with Mature Plasmodium Falciparum Parasites in Papua New Guinea

Antigens were detected on the surface of erythrocytes from children with acute falciparum malaria in Madang, Papua New Guinea. These parasite-induced erythrocyte surface antigens (PIESA) were serotyped with convalescent sera from children and hyperimmune sera from adults in parasite infected cell agglutination assays (PICAs) and by inhibition of binding of infected cells to melanoma cells. Extensive serological diversity of PIESA was demonstrated. A significant correlation between serotypes defined by reactivity of immune sera in PICA and inhibition of melanoma cell binding (MCB) was observed. This suggests that both assays measure antibody responses to the same antigen(s). Increased recognition of different PIESA specificities with age is consistent with the hypothesis that repeated exposure to malaria confers immunity against a range of PIESA serotypes and parallels the development of clinical immunity to malaria in this area of Papua New Guinea.

Characterization of the Cryptosporidium antigens from sporulated oocysts of Cryptosporidium parvum.

The antigenic constituents of sporulated Cryptosporidium parvum oocyst antigens were characterized with antisera from mice immunized against C. parvum. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining defined the major proteins. Six of seven lectins used recognized as many as 15 bands. The lectins concanavalin A, Dolichos biflorus, and wheat germ agglutinin showed strong activity against the same eight bands with molecular weights ranging from 72,000 to greater than 100,000. An enzyme-linked immunosorbent assay was used to detect antibody to C. parvum. Antibody binding was significantly decreased by heat and enzymatic treatment with trypsin, protease, and mixed glycosidases. C. parvum antigens were further defined by the reactivity of immune sera with a C. parvum sonicate preparation separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoretically transferred to nitrocellulose paper. Antisera from orally infected mice consistently recognized four antigens with molecular weights ranging from 72,000 to greater than 100,000. These antigens also bound concanavalin A. Treatment of the antigen preparation with mixed glycosidases reduced the reactivity of antisera with most antigens with molecular weights greater than 60,000. The data suggest that the antigenic composition of C. parvum is complex and that carbohydrates alone or in association with lipids or proteins may be important in the immune response to C. parvum.