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Biomedical subjects

S Dray

Publications and source records attributed to S Dray.

At least 109 records · Page 6Linked to original sources
PubMed1976

Immunoglobulin content and antibody activity in an artificial body cavity.

Artificial body cavities (ABC) were created by the insertion of hollow polyethylene balls in the subcutaneous tissue of rabbits. After two months no inflammatory reaction could be detected, the ABC was enveloped by a membranous structure, and the cavity contained about 20 ml of fluid. The protein concentration was about 3 times, and the IgG about 8 times, lower in the ABC fluids than in the corresponding serum. At the same time the antibody titers against sheep red blood cells (SRBC), human IgG and herpes simplex virus type 1 (HSV) were about 20 200 times lower than in the corresponding serum samples. The IgG molecules appeared to be undamaged as shown by the presence of various allotypes and by the elution pattern from G-200 column. Testing the protective activity of ABC fluids and of serum against HSV infection showed that ABC fluids had no protective activity. The experiments suggest that the membranous structure selected among classes of Ig and probably among other serum proteins. In addition, the IgG molecules with antibody activity against various inoculated antigens were selectively excluded to penetrate in the ABC. The ABC might be considered analogous to virtual cavities of the body surrounded by membranes and possibly to the extravascular compartment.

Animals↗
PubMed1976

Enumeration and isolation of rabbit T and B lymphocytes by using antibody-coated erythrocytes.

Rosette formation with antibody-coated erythrocytes (Ab-E) was employed for the enumeration and isolation of rabbit B cells (Ig+T-) and T cells (Ig-T+). The cells bearing surface Ig (Ig+ cells) were enumerated by a direct immunocytoadhesion technique utilizing anti-rabbit IgG antibody-coated erythrocytes (Ab-E). To enumerate cells bearing thymus cell antigen (T+ cells), an indirect rosette technique was used in which lymphocytes were first sensitized with guinea pig anti-rabbit thymus cell antiserum and then rosetted with anti-guinea pig IgG Ab-E. To demonstrate the specificity of the anti-thymus cell antiserum, a 51Cr radioimmunoassay for counting rosettes was employed along with visual counting to enumerate Ig+ and T+ cells in lymph node cell populations. When Ig+ and T+ lymph node cells were rosetted simultaneously with sheep and human erythrocytes, no mixed rosettes (less than 1%) were observed. Ficoll-Hypaque gradient centrifugation was used to obtain purified Ig+T- and Ig-T+ cells by removing rosetted T+ and Ig+ cells, respectively. The purity of isolated Ig-T+ cells was indicated by 94 to 95% indirect rosetting with anti-thymus cell antiserum and by 0 to 3% direct rosetting with anti-rabbit IgG Ab-E. The purity of isolated Ig+T- cells was indicated by 90 t0 94% direct rosetting with anti-rabbit IgG Ab-E and by 2 to 3% indirect rosetting with anti-thymus cell antiserum. The percentage of Ig+T- and Ig-T+ cells were determined in peripheral blood and in various lymphoid organs. The isolated Ig+T- and Ig-T+ cells were also characterized by their responses to mitogens. Thus, nearly pure Ig+T- and Ig-T+ cells were isolated by "negative selection," which should minimize functional changes of the cells, and thereby facilitate the study of their biologic properties, e.g., their response to mitogens.

Animals↗
PubMed1976

Effect of VHa locus allotype-suppression on the expression of closely linked VHx, VHy, and Cmun genes in heterozygous rabbits.

Injection of a1x-y-n81/a2x32y33n82 heterozygous rabbit at birth with anti-a2 allotype antiserum suppresses the production of the VHa2 gene product a2 Ig as well as the expression of the closely linked Cmun gene product n82 but not of the closely linked VHx and VHy gene products x32 and x33. This effect is related to the appearance of a2 and n82 on the same IgM molecules whereas a2, x32, and y33 appear on different Ig molecules.

Animals↗
PubMed1976

Heavy chain variable region allotypic sub-specificities of rabbit immunoglobulins. I. Identification of three subpopulations of a1 IgG molecules.

Four anti-al Ab subpopulations were isolated from an anti-al antiserum by sequential immunoadsorption chromatography. These four anti-al Ab subpopulations were differentially bound by two "limited heterogeneity" Abs having different components of the al allotypic specificity. Each of the four anti-al Ab subpopulations reacted with al IgG molecules obtained from a2 and a3 rabbits. A subpopulation designated anti-al Ab reacted with 100% of al IgG molecules. Thus, the anti-al-A Ab recognizes al determinants common to all al IgG molecules. Each of the other three subpopulations, designated anti-al-B Ab, anti-al-C Ab, and anti-al-D Ab, reacted with only a fraction of the al IgG molecules but the sum of the percentages of al IgG molecules which reacted with each of these three anti-al Ab subpopulations approximated 100% of the al IgG molecules. Thus each of the anti-al-B Ab, anti-al-C Ab, and anti-al-D Ab recognizes non-common determinants distinct for each of three subpopulations of al IgG molecules. Although 65 to 90% of IgG molecules in al homozygous rabbits have the al allotypic specificity, these IgG molecules are heterogeneous with respect to their antigenic determinants comprising the al allotype; at least three kinds of al IgG molecules are identified. This heterogeneity probably reflects variation in the amino acid sequence of the Vh region of al IgG molecules and, therefore, poses a similar argument which had led to the hypothesis of two genes for one polypeptide chain and to the theory of episomal insertions for the genetic control of immunoglobulin synthesis.

Animals↗
PubMed1976

Synchronous regulation of VH and CH allotypes among Ig molecules in multi-heterozygous rabbits suppressed with anti-VH allotype antibody: emergence of IgA from suppression prior to IgG and IgM.

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were suppressed at birth for the VH region a1 allotype. At 8 weeks of age, quantitative analysis of serum IgG, IgM, and IgA molecules showed that the VHa1 specificity was effectively suppressed in the three classes of Ig and that the suppression was extended to the CH region n81 specificity on mu-chains as well as to the CH region f73 and g74 specificities on alphaf and alphag chains. At 26 weeks of age, analysis of serum IgG and IgM molecules showed that a1 was still suppressed to approximately the same extent in both Ig classes and the suppression was still extended to the CH region n81 specificity. However, at 26 weeks, the percentage of molecules with a1 specificity had doubled among serum and colostral IgA molecules and this increase was extended to the CH region f73 and g74 specificities. Thus, the suppressed allotypes reappeared first among IgA molecules. Our data are consistent with a regulatory mechanism which controls and synchronizes the expression of the VHa and the CH allotypes expressed on the same heavy chain. The order of the re-expression of the suppressed allotypes with respect to Ig class may allow further definition of selective regulatory mechanisms for the synthesis of Ig classes.

Animals↗
PubMed1975

A general method for enumerating single cells secreting antigen: albumin-secreting hepatocytes detected as plaque-forming cells.

Sheep erythrocytes, artificially coated with purified antibody specific for mouse serum albumin (anti-MSA Ab-E) were agglutinated and lysed by mouse serum albumin. Mouse liver cells, plated with anti-MSA Ab-E formed hemolytic plaque in a modified plaque-forming cell (PFC) assay. The same cells tested with anti-MSA Ab-E did not rosette in modified immunocyto-adhesion assay. Thus, liver cells secreted molecules (albumin) which were not detectable on the cell membrane. This PFC assay with Ab-E is probably a general method for enumerating antigen-secreting cell.

Agglutination↗
PubMed1975

A simple radioimmunoassay for the enumeration of rosette-forming cells.

A simple radioimmunoassay for the enumeration of Ig bearing (Ig+) lymphocytes by rosette formation with anti-Ig, antibody coated erythrocytes (Ab-E) is described. The method is based upon labeling lymphocyte populations with 51Cr, rosetting them with Ab-E, separating the rosetted from unrosetted cells by centrifugation through a Ficoll-Hypaque layer, counting the radioactivity of the unrosetted cells, and counting the radioactivity of the unrosetted cells in a rosetting system with unreactive uncoated-E. This permits the calculation of the percentage of rosette-forming Ig+ cells. The assay eliminates the subjectivity and tediousness of counting and distinguishing between rosetted and unrosetted cells under the microscope. Being also sensitive and reliable, this radioimmunoassay may, after suitable modifications, replace the conventional counting of other types of rosettes.

Animals↗
PubMed1975

Tumor regression at an untreated site during immunotherapy of an identical distant tumor.

The effects of two immunotherapy regimens on the development of an untreated, uniformly lethal transplantable line-10 hepatoma in strain 2 guinea pigs were monitored during treatment of an identical tumor 10 cm away. Line-10 cells were injected intradermally simultaneously at each of two sites. When one site was treated 6 and 16 days later with rabbit antibody against guinea pig fibrin fragment E, the complete regression of the treated tumor, a 25--30% depression in the development of the untreated tumor, and an increased survival time were observed. In another group of animals, when one site was treated 5 days after tumor challenge with syngeneic or xenogeneic "tumor-immune" RNA in a regimen including syngeneic nonsensitive lymphoid cells and tumor-specific antigen, all animals survived after complete and apparently specific regression of the tumors at both the treated and untreated sites. For the RNA regimen, we have shown that immunotherapy of an intradermally established line-10 tumor results in complete abrogation of both the treated and a distant untreated tumor; i.e., demonstrating a systemic effect.

Animals↗
PubMed1975

Enumerating immunoglobulin-secreting cells among peripheral human lymphocytes. A hemolytic plaque assay for a B cell function.

Cells bearing immunoglobulin (Ig) can be enumerated by current methods, but cells secreting Ig (with unknown antibody specificity) can not. By using a reverse plaque-forming cell assay, we counted the Ig-secreting cells in the blood of nonimmunized individuals. Isolated human lymphocytes were plated in gels together with erythrocytes coated with purified antibody to human Ig. After treatment with anti-Ig antibody and complement, the Ig-secreting cells formed hemolytic plaques. In 10 normal individuals, 1.2 +/- 0.4% of the plated mononuclear cells formed plaques; in an individual tested on 7 different days during 3 months, 1.1 +/- 0.2% of the cells formed plaques. From the number of mononuclear cells in the blood, we calculated 22 +/- 8 Ig-secreting cells per mm3 of blood. Enumerating Ig-secreting cells is a new direct assay for a B cell function and need not correlate with quantitating serum Ig. Thus, this assay should be useful for studying Ig-secretion in normal and altered states.

Animals↗
PubMed1975

Maintenance of lymphocyte surface Ig by mitogen stimulation in vitro.

In 4 to 24 hr cultures of rabbit lymphoid cells in medium supplemented with autologous serum, most B cells lost their surface Ig as assayed by rosette formation with anti-Ig antibody-coated erythrocytes. This loss was prevented by adding selected mitogens such as streptococcal mitogen (SM), lipopolysaccharide, and concanavalin A or by supplementing the medium with fetal calf serum. When SM was added at various times to the cultures (1, 2, 3, and 4 hr), it was effective in maintaining the approximate level of Ig-bearing cells present at the time of its addition but was ineffective in restoring the level of Ig-bearing cells present at the time the cultures were intiated. Very small, submitogenic doses of SM were sufficient to maintain the level of Ig-bearing cells. The data suggest that lymphocytes require continuous stimulation to maintain their surface receptors.

Animals↗
PubMed1975

Complete and apparently specif local tumor regression using syngeneic or xenogeneic "tumor-immune" RNA extracts.

Syngeneic and xenogeneic RNA-rich extracts of lymphoid tissues were used in an immunotherapeutic regimen to treat strain 2 guinea pigs that were given intradermal injections of a uniformly lethal dose (1 x 10(6)) of line 10 diethylnitrosamine-induced transplantable hepatoma cells. When 1 X 10(7) syngeneic nonsensitive peritoneal exudate cells, 2.5 mg RNA from line 10-immune strain 2 guinea pigs or line 10-immune Rhesus monkeys, and 1.0 mg of a line-10 tumor-specific antigen preparation were injected s.c. under the tumor cells injected 5 days previously, complete local tumor regression in all treated animals was observed. If either nonsensitive peritoneal exudate cells, RNA, or line 10 tumor-specific antigen was omitted, or if Escherichia coli RNA or RNA from animals sensitized to a different tumor (line 1) was used, little or no tumor regression was observed, suggesting that the action of the RNA may have resulted in an antitumor response specific for the noplasm being treated. The long-term tumor-free survival of all treated animals indicates that the action of the RNA is systemic, since metastases are known to occur frequently by the time our therapeutic regimen was given. Also, in testing the biological activity of the "tumor-immune" RNA in the in vitro cell-migration-inhibition assay, both the syngeneic and xenogeneic RNA extracts could transfer tumor-specific immunological sensitivity, as demonstrated by the elaboration of migration-inhibitory factor by the RNA-treated nonsensitive peritonial exudate cells in the presence of the line 10 tumor-specific antigen.

Animals↗
PubMed1975

Rosetting of antibody-sensitized tumor cells with anti-immunoglobulin antibody-coated erythrocytes by a new method for detecting antigens on cells.

Tumor cells were treated with rabbit antibody to tumor-associated cell surface antigens and tested with erythrocytes coated with antibody specific for the sensitizing rabbit immunoglobulin. The sensitized tumor cells formed rosettes with the indicator cells. By this method, we confirmed that line 1 and line 10 hepatoma cells (from two tumors independently induced by diethylnitrosamine in strain 2 guinea pigs) bear antigens not present on normal liver cells. We also confirmed that line 1 and line 10 cells bear antigenically different tumor-associated cell surface antigens. This method appears simpler than other serological methods for detecting tumor-associated cell surface antigens on tumor cells. Also, this method may be a general one for detecting and enumerating cells bearing surface antigens.

Animals↗
PubMed1975

Complete local tumor regression with antibody to fibrin Fragment E.

Rabbit antibody to fibrin fragment E (FFE) was used in an immunotherapy model for the treatment of the line-10 ascites variant of a diethylnitrosamine-induced hepatoma in strain 2 guinea pigs. When 0.75 or 1.0 mg of an IgG preparation containing anti-FFE antibody was injected s.c. 6 and 16 days after the injection of a uniformly lethal dose of line-10 tumor cells, complete regression of the i.d. growing tumor was observed in all 18 strain 2 guinea pigs treated. Thus, this therapy appears to be more effective than any BCG or other immunotherapeutic regimen thus far reported for this tumor. No significant anti-tumor effect was noted when normal rabbit IgG or smaller doses (0.25 or 0.50 mg) of the anti-FFE IgG preparation were used. The injection sites exhibited an inflammatory response for 7 to 10 days characterized by erythema and hemorrhage. Since all animals were treated after the metastatic progression of the tumor is known to frequently occur, the long-term tumor-free survival of these animals as well as their resistance to subsequent tumor challenge indicate that the anti-FFE antibody therapy led to systemic tumor immunity.

Animals↗
PubMed1975

Enumeration and isolation of human T and B lymphocytes by rosette formation with antibody-coated erythrocytes.

Rosette techniques are presented for the enumeration and separation of both Ig+ T- and Ig- T+ human lymphocytes. In order to enumerate Ig+ cells, the direct immunocytoadhesion technique was employed using human erythrocytes (E) coated with purified anti-kappa or anti-lambda light chain antibodies. Specificity of these rosettes was shown with chronic lymphocytic leukaemias of either the kappa or lambda type. T+ cells were enumerated by a new indirect rosette technique in which the lymphocytes were initially treated with rabbit anti-human thymus cell antiserum followed by direct rosetting with human E coated with purified anti-rabbit light chain antibody. For normal individuals, 24-32% Ig+ T- cells and 65-71% Ig- T+ cells were found among the lymphocytes of peripheral blood as well as tonsils with these rosette methods. The Ficoll-Hypaque method was used to obtain purified Ig- T+ and Ig+ T- cells by removing rosetted Ig+ cells or T+ cells, respectively. The purity of the Ig- T+ cells was indicated by greater than 99% indirect rosetting of cells sensitized with anti-human thymus cell antibody (Ab) and by less than 1% direct rosetting with anti-kappa Ab-E+ anti-lambda Ab-E. The purity of the Ig+ T- cells obtained was indicated by 92-96% direct rosetting with anti-kappa Ab-E+anti-lambda Ab-E and by less than 1% indirect rosetting with anti-human thymus cell antibody. A small percentage of Ig- T- 'null' cells could not be identified by either reagent. Thus, essentially pure Ig- T+ and Ig+ T- cells were readily and efficiently isolated by 'negative selection' thereby lessening the possibility of functional changes that may develop by more extensive manipulation of lymphocytes.

Antibodies↗