Immunochemistry最新文献

These studies show that human peripheral mononuclear cells have a surface receptor of 60,000 mol. wt (and possibly a disulfide bonded dimeric form of 120,000) which has affinity for heat-aggregated human IgG, IgG₁ myeloma proteins, or the Fc⁺ fragments of either of these but not to F(ab')₂ fragments of IgG. Precipitates of this receptor contain 0.5–1% of the total number of TCA precipitable counts incorporated into the surface membrane. Since this structure was found trysininsensitive and was not identified on the cell membranes of cultured human T cell lines, it appears to be a surface receptor for the Fc portion of IgG.

1. When a carrier-hapten complex was used to raise antibodies in rabbits against ceramidetrihexoside, an antiserum was obtained in which the activity against the carrier could not be removed by absorption with the carrier without loss of the anti-hapten activity.

2. Antibodies against ceramidetrihexoside were raised in rabbits by immunizing them with a mixture of bovine serum albumin and the glycolipid according to Hakomori (1972). It was found that these antibodies cross-reacted with digalactosylceramide. but not with lactosylceramide or digalactosyldiglyceride. No cross-reactivity was observed with globoside in an artificial membrane system but a slight cross-reactivity was found with globoside absorbed on cholesterol microcrystals. A possible explanation for the latter phenomenon is discussed. From inhibition studies with different sugar compounds combined with the cross-reactivity studies, it can be concluded that anti-ceramidetrihexoside antibodies have a high and strict specificity for a terminal galactosyl α(1→ 4)galactosyl group.

3. Antibodies raised in rabbits against globoside by the method of Hakomori (1972) did not cross-react with the other glycolipids tested. The characteristics of these antibodies are compared with those of the anti-ceramidetrihexoside antibodies.

4. A human anti-P₁,P,P^k serum from a person with the rare phenotype p, which contains anticeramidetrihexoside (anti-P^k) activity was compared with the rabbit anti-ceramidetrihexoside serum. The two antisera showed very similar characteristics with regard to the anti-ceramidetrihexoside activity.

Purified di- and hexamannoside components ofMycobacterium 607 (M. 607) were analysed for their immunochemical relationships in agglutination and precipitation tests, using antisera against the MBSA complexes of total mannosides, M₂-3F^† and M₂-4F components of dimannosides. The agglutinating antibody to total mannosides seemed to be different from that given by the precipitation test. There was no cross-reactivity between PI and the mannoside antigens, which suggested the association of antigenicity with the mannose units of the mannosides. Dimannosides with 2, 3 and 4 esters showed complete cross-reactivity. However, different antigenic specificities were found to be associated with di- and hexamannoside antigens in the immunochemical reactions. The deacylated mannoside lacked serological reactivity with antiserum to the mannosides. However, the additional fatty acids in the inositol-oligomannosyl region of the dimannosides did not seem necessary for reactivity or specificity.

An organ specific (common histotypic) antigen has been identified and partially purified from a spontaneously metastasizing rat mammary carcinoma, TMT-081. The antigen is present in the tumor at a level about 50–200 times greater than in non-malignant, hyperplastic mammary tissue.

The antigen is a membrane associated glycoprotein and was solubilized by limited papain digestion of tumor cell membranes or by extraction with non-ionic detergent. Partial purification of papain solubilized antigen by gel filtration and lectin affinity chromatography yielded material that was 50% precipitable by a specific rabbit antibody reagent obtained from antiserum raised against the tumor. The apparent molecular weight of the partially purified antigen was about 28.000 as determined by SDS-PAGE. Quantitation of the antigen was accomplished by a sensitive binding inhibition radioimmune assay. The antigen was present in hyperplastic mammary tissue and was not detected in other normal adult or fetal rat tissues and in a polyoma virus induced syngeneic rat fibrosarcoma. The antigen could be detected in the serum of tumor bearing animals at concentrations reflecting the tumor mass present.

The content and the avidity curves of IgM-positive spleen B lymphocytes forming rosettes with TNP-SRBCI were compared in C57BL/6 and BALB/c mice (C57BL/6 × BALB/c)F₁ hybrids, as well as F₁ × C57BL/6 and F₁ × BALB/c backcross hybrids. Conjugates of bovine serum albumin with trinitrophenyl. dinitrophenylsulfonic and sulfanilic acids were used as inhibitors (TNP₂₄BSA, DNP₂₃BSA, Sulf₁₇BSA).

The spleen TNP-RFC content in BALB/c mice was 60% higher than in the C57BL/6 strain. F₁ hybrids were intermediate in this respect. F₁ × BALB/c hybrids had on the average 35% more TNP/RFC than F₁ × C57BL/6 mice.

The TNP-RFC inhibition (avidity) curves obtained with TNP₂₄BSA, DNP₂₃BSA and Sulf₁₇BSA were markedly different in BALB/c, C57BL/6 and (BALB/c × C57BL/6)F₁ animals. We conclude that the spleen content and avidity of TNP-RFC in mice are subject to strict genetic control.

Assuming random expression of V (idiotype?) genes, the present results seem to indicate that the content and proportions of groups of B clones are controlled by structural immunoglobulin genes. The simplest control mechanism could be provided by definite quantitative relationships between corresponding groups of V genes.

The Ia antigens from strain 2 and strain 13 guinea pig lymphocytes were solubilized with the non-ionic detergent Nonidet P-40* (NP-40) and purified by two simple affinity chromatography steps. The first step consisted of lentil lectin chromatography from which a glycoprotein-enriched fraction was obtained. The final step consisted of chromatography using la-specific immunoabsorbents, from which the antigens were eluted with acid glycine buffer. Antigen yields were determined by inhibition of cytotoxicity, and mean yields were 21% for the strain 13 Ia antigens and 19% for the strain 2 Ia antigens. Electrophoretic analysis demonstrated the high degree of purification attained. Immunoabsorbent chromatography offers a rapid and effective method for the isolation of Ia antigens.

Purification of the surface antigen ofParamecium tetraurelia (termed i-antigen) by previously published procedures has been shown to result in preparations which frequently contain contaminating proteins including a thiol-activated protease. Alternate procedures for the purification of i-antigen were developed using ion-exchange chromatography. While certain of these procedures result in a homogeneous preparation of i-antigen, the poor yields obtained make these procedures impractical. An alternate method for the purification of i-antigen was developed using immunoaffinity chromatography. Purification by this technique proved to be superior to the various standard procedures described previously. The immunoaffinity column is rapid and results in a recovery, on the average, of over 95% of the applied material. The columns are readily regenerated and may be used numerous times without loss of capacity or purification ability. The i-antigen purified by this method appears homogeneous immunologically and electrophoretically on polyacrylamide gel electrophoresis and isoelectric focusing.

Pre-incubation of BSA-anti-BSA precipitates with Clq or bivalentStaphylococcus protein A inhibits the solubilization of the precipitates due to the complement dependent complex release activity (CRA) of fresh sera. The inhibition was dose dependent. The results support the intercalation hypothesis of CRA.