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D G Haegert

Publications and source records attributed to D G Haegert.

53 records · Page 3Linked to original sources
PubMed1979

Phagocytic peripheral blood monocytes from rabbits and humans express membrane receptors specific for IgM molecules: evidence that incubation with neuraminidase exposes cryptic IgM (Fc) receptors.

Phagocytic human and rabbit peripheral blood monocytes, identified by their ingestion of polystyrene particles, were investigated for the presence of surface membrane receptors for IgM molecules. After incubation of freshly isolated monocytes with IgM anti-sheep erythrocyte (SRBC) preparations, a mean of 0.7% of human monocytes and a mean of 16.2% of rabbit monocytes formed rosettes with SRBC. However, if the monocytes were pre-incubated with vibrio cholerae neuraminidase (VCN), these figures increased to 32.6% and 37.8% respectively. The specificity of rosette formation by VCN-treated monocytes was established in several experiments; SRBC sensitized with a F(ab')2 preparation of an IgG anti-SRBC reagent completely failed to rosette with VCN-treated monocytes, and inclusion of IgM, but not other Ig or non-Ig protein molecules in the test medium, inhibited rosette formation. Further, and most important, rosette formation by human monocytes was inhibited by F(c)5mu but not by Fabmi fragments. These findings indicate that both rabbit and human monocytes express IgM-class specific membrane receptors for IgM molecules, that these receptors may be cryptic or hidden but can be revealed by treatment with VCN and that the human monocyte IgM receptor is F(c) specific. Further, the rabbit monocyte IgM receptor was shown to be trypsin-resistant.

Animals↗
PubMed1978

Technical improvements in the mixed antiglobulin rosetting reaction with consequent demonstration of high numbers of immunoglobulin-bearing lymphocytes in viable preparations of human peripheral blood.

A modification of the mixed antiglobulin rosetting reaction (MARR) to improve sensitivity as a test for immunoglobulin (Ig)-bearing human blood lymphocytes is described. A mean 5.7%, lymphocytes Ig-positive by the MARR when rosettes were formed in medium containing 0.2% bovine serum albumin (BSA), increased to 20% when rosettes were formed in 5% BSA or by incubating the lymphocytes or indicator erythocytes with Vibrio cholerae neuraminidase before rosetting. Under these various rosetting conditions the MARR is as sensitive as the direct antiglobulin rosetting reaction (DARR). Further, with the MARR, false positive rosette formation due to unusual antimembrane antibodies can be excluded during the mixed antiglobulin rosetting procedure by use of blocking controls. Substitution of F(ab)2 antiglobulin for IgG anti-gamma, anti-alpha and anti-mu did not reduce the number of lymphocytes demonstrable with the MARR, indicating that the MARR does not react with adsorbed Ig molecules on lymphocytes. Summation of the number of sheep erythrocyte (E) rosetting lymphocytes and mixed antiglobulin rosetting lymphocytes approximated 100%, yet in T-enriched preparations a maximum of 4% of lymphocytes were Ig-positive by the MARR, suggesting that null lymphocytes which have been reported to be E-negative and immunofluorescence-negative are B lymphocytes with surface Ig determinants.

Animals↗
PubMed1978

Comparison of the direct antiglobulin rosetting reaction with direct immunofluorescence in the detection of surface membrane immunoglobulin on human peripheral blood lymphocytes.

Comparisons were made between the Direct Antiglobulin Rosetting Reaction (DARR) and Direct Immunofluorescence (DIF) in the detection of surface membrane immunoglobulin of human peripheral lymphocytes. The DARR was more sensitive and the results with this testing procedure (as opposed to those with the DIF) were not influenced by various treatments of the lymphocytes before testing, such as incubation in AB serum at +/- 4 degrees, incubation in serum-free medium at 37 degrees or short exposure to acetate buffer at pH 4.0. Again the DARR (as opposed to the DIF) gave essentially the same results whether the red cell-linked antiglobulin was IgG or the F(ab')2 preparation. With mixed rosetting for both T and SmIg+/- lymphocytes, there was only 1% or less null cells and only 5% or less lymphocytes rosetted with both marker red cells.

Antibodies, Anti-Idiotypic↗
PubMed1977

Neuraminidase- and trypsin-induced exposure to membrane receptors for IgG and IgM molecules on human peripheral blood lymphocytes.

Brief incubation of human peripheral blood lymphocytes with vibrio cholerae neuraminidase (VCN) or trypsin revealed hidden membrane receptors for IgG and IgM molecules. The hidden receptors were found on T lymphocytes as shown by double-label and mixed rosetting experiments and by studies of T-enriched populations. Although IgM receptors were undetectable on freshly isolated lymphocytes, a mean of 17.1% of VCN-treated lymphocytes rosetted with ox erythrocytes coated with IgM antibody (EA-IgM). Prior to trypsin treatment a mean of 14.6% of human T lymphocytes rosetted with ox red cells coated with IgG antibody (EA-IgG). After incubation with trypsin this figure increased significantly (P less than 0.005) to 44.5%. VCN-treatment also significantly increased (P less than 0.005) the mean percentage of EA-IgG rosette-forming T cells to 38.5%. The T-cell receptor for IgG was shown to be trypsin-resistant while the IgM receptor was shown to be trypsin-sensitive. Using mixed rosettes, a tentative T-cell subset was identified which expressed both IgG and IgM membrane receptors. Also, a minor subset with IgM receptors alone and a larger subset with only IgG receptors were identified.

Binding Sites, Antibody↗
PubMed1976

Immunoglobulin-positive mononuclear cells in human peripheral blood: detection by mixed anti-globulin and direct anti-globulin-rosetting reactions.

Ig-bearing mononuclear cells were identified in Ficoll-Hypaque preparations of human peripheral blood by using mixed anti-globulin (MAG) and direct anti-globulin rosettes; indicator cells consisted of sheep erythrocytes coated with human F(ab')2 or anti-F(ab')2 antibody, respectively. Of the cell population isolated from 10 normal subjects, a mean of 68% was lymphocytes. However, fewer than 50% of the cells with detectable surface Ig were lymphocytes. On viable cell preparations using chromic chloride-treated sheep erythrocytes (CrCl3SRBC) coated with anti-F(ab')2 antibody, a mean of 20.1% of the lymphocytes formed rosettes, i.e., were B. Up to 6% of peripheral blood lymphocytes formed mixed Ig-rosettes and E-rosettes. On viable lymphocytes using F(ab')2-coated CrCl3SRBC, MAG rosettes were insensitive in detection of B lymphocytes. Formaldehyde treatment of lymphocytes increased the number of B cells detectable to 25.5% of the lymphocyte population. Study of T-enriched and B-enriched populations showed that the observed increase in B cell reactivity was real and not due to MAG-rosetting T cells. A one-stage procedure for T and B lymphocyte separation is described.

Antibodies, Anti-Idiotypic↗
PubMed1976

T and B lymphocytes and Reed-Sternberg cells in Hodgkin's disease lymph nodes and spleens.

Lymphoid cells from twenty-four untreated Hodgkin's disease biopsies were examined for spontaneous sheep erythrocyte and sensitized ox erythrocyte rosette formation for the identification of T cell and cells with Fc and C3 receptors and surface immunoglobulin. Compared with normal tissues mean T-lymphocytes values were elevated in both involved lymph nodes and uninvolved spleens from Hodgkin's patients. Lymphocytes bearing C3 receptors were correspondingly reduced in these tissues. Involved spleen T-cell values fell within the normal range. In normal tissues the sum of lymphocytes with surface immunoglobulin and sheep erythrocyte receptors fell in the range 89-108%. In six biopsies of Hodgkin's tissue the sum was outside the normal range (121-142%). This observation is compatible with surface immunoglobulin-coated T cells. Surface marker characteristics and intracellular immunoglobulin studies of small lymphocytes, lymphoblasts and Hodgkin's cells suggested that the neoplastic cells were of B lymphocyte origin.

Adolescent↗
PubMed1975

Acute lymphoblastic leukaemia: a heterogenous disease.

By using several techniques to detect surface markers on T and B lymphocytes, 11 cases of acute lymphoblastic leukaemia (A.L.L.) were studied. In four cases an insignificant number of markers were detected on the lymphoblast populations. In one case a significant number of blasts formed both sheep red blood cell rosettes and Fc rosettes, suggesting a T-cell origin for the neoplastic cells, and in another case the presence of Fc and C3 receptors on the lymphoblast population indicated a B-cell origin. In a further five cases 14-43% of the blasts had detectable surface immunoglobulin. It is concluded that A.L.L. is a heterogeneous disorder, some cases failing to express surface markers and others having either a T-or a B-lymphocyte origin or both.

Adolescent↗
PubMed1975

Increased sensitivity of the rosette-forming reaction of human T lymphocytes with sheep erythrocytes afforded by papain treatment of the sheep cells.

Human T lymphocytes are known to adhere to sheep erythrocytes. This affinity reaction was found to be consistently increased following treatment of the sheep cells with papain. Reactions with treated erythrocytes were more stable and involved higher percentages of lymphocytes. Using a double marker system of papain-treated sheep erythrocytes together with Fc rosettes as a presumptive B-cell marker, there was an overlap population of only 1% lymphocytes. Sheep erythrocytes treated with papain therefore appear to remain specifically adherent to human T lymphocytes.

Animals↗
PubMed1974

Combined T and B cell acute lymphoblastic leukaemia.

A case of acute lymphoblastic leukaemia in a 17-year-old male is described. The patient had many distinctive features including a very high blast cell count, prominent lymphadenopathy and hepatosplenomegaly, thymic mass, and a fulminant clinical course. Immunological studies on the blast cells using a variety of techniques showed the presence of two distinct subpopulations, one having the surface characteristics of thymus-dependent (T) lymphoid cells and the other those of bursa-equivalent (B) lymphoid cells. The case therefore represents the first example of a combined T and B cell acute leukaemia.

Adolescent↗
PubMed1974

Leukaemic reticuloendotheliosis: a morphological and immunological study of four cases.

Morphological and immunological studies of four cases of leukaemic reticuloendotheliosis are reported. The findings indicate that leukaemic reticuloendotheliosis is a monoclonal B cell neoplasm in which the leukaemic cell expresses either Kappa or lambda light chain and delta heavy chain determinants. The similarity between this disease and chronic lymphocytic leukaemia is discussed.

Acid Phosphatase↗
PubMedDate not supplied

T cell antigen receptors.

T cells play an important role in regulating the immune response to virtually all antigens. Central to the functioning of these lymphocytes is their capacity to recognize and respond to antigen. Although the T cell receptor has yet to be defined in precise terms, considerable information has accrued concerning its structure and function. This article discusses certain aspects of T cell recognition which are required for a general understanding of the physiology of an immune response and which may eventually permit selective modulation of a specific immune response in various patients including those with neoplastic disorders.

Histocompatibility Antigens Class II↗