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J F Kearney

Publications and source records attributed to J F Kearney.

At least 145 records · Page 8Linked to original sources
PubMed1980

Differentiation of human B cells expressing the IgA subclasses as demonstrated by monoclonal hybridoma antibodies.

Monoclonal hybridoma antibodies to the human IgA subclasses were produced by immunizing mice with purified myeloma proteins. These antibodies were shown to be specific for the appropriate IgA subclass by enzyme-linked immunoabsorbant assay (ELISA) and by immunofluorescent staining of myeloma plasma cells and B cells from normal individuals. These antibodies were used to demonstrate age-related shifts in the proportions of IgA1- and IgA2-bearing B cells that could be correlated with 3 distinct staining patterns. In the newborn equal numbers of IgA1 and IgA2, B cells were found. These cells had only small amounts of surface IgA in a patchy distribution. They also expressed surface IgM. In the infant, large lymphoblastoid cells were observed that bore more IgA in a homogeneous pattern but did not express IgM. Of these cells, 98% were positive for IgA1. In the adult, 80% of the IgA B cells were positive for surface IgA1, and 20% were positive for IgA2. These were small lymphocytes brightly stained for IgA and negative for IgM. In culture, the adult B cells responding to pokeweed gave rise to roughly equal numbers of IgA1 and IgA2 plasma cells. These results suggest that there are equal numbers of precursor cells for IgA1 and IgA2 whose expansion, further differentiation, and migration are selectively affected by immunoregulatory controls.

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PubMed1979

A new mouse myeloma cell line that has lost immunoglobulin expression but permits the construction of antibody-secreting hybrid cell lines.

We have isolated a subclone of the mouse myeloma cell line P3-X63-Ag8 that does not express immunoglobulin heavy or light chains. This clone X63-Ag8.653 can be used for efficient fusion with antibody-forming cells to obtain hybrid cell lines producing pure monoclonal antibodies. Screening of hybrid cell lines for specificity and immunoglobulin classes was done with a modified enzyme-linked immunosorbent assay.

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PubMed1978

Sequential expression of immunoglobulin on developing mouse B lymphocytes: a systematic survey that suggests a model for the generation of immunoglobulin isotype diversity.

Paired immunofluorescent staining with antibodies specific for the major isotypes of mouse immunoglobulin was used to study the ontogenetic expression of diversity of cell surface immunoglobulin. The first B lymphocytes to emerge, derived from cytoplasmic IgM+ precursors, express sIgM exclusively. Between birth and 3 days of age separate populations of sIgM+ B lymphocyte acquire a second isotype: sIgD, one of the subclasses of sIgG, or sIgA. At 3 days, all splenic B lymphocytes that bear sIg or sIgA also express sIgM, but virtually none stain for sIgD. By 7 days, a substantial porportion of sIgG+ or sIgA+ lymphocytes in spleen and most of those in lymph node express both sIgM ans sIgD. Anti-mu antibody treatment from birth prevented development of B lymphocytes expressing any isotype. These observations suggest that the immature sIgM+ B lymphocyte is the pivotal cell in the generation of the different sublines of B cells and that sIgD ig or IgA. The frequency of lymphocytes bearing only sIgG or sIgA is higher in old than in young mice, suggesting that sIgD and sIgM may be lost after stimulation by antigens. The occurrence of a nearly identical distribution of sIg isotypes on B lymphocytes from athymic, pathogen-free mice suggests that primary expression of isotype diversity does not require T cells.

Aging↗
PubMed1978

Pre-B cells: bone marrow persistence in anti-mu-suppressed mice, conversion to B lymphocytes, and recovery after destruction by cyclophosphamide.

Chronic treatment of mice from birth with anti-mu antibodies aborts development of B lymphocytes and plasma cells. In these studies we show that bone marrow from anti-mu-treated mice contains a population of cells with cytoplasmic IgM, but which lack detectable cell-surface IgM. These cells are analogous to pre-B cells, defined in ontogenetic studies as the immediate precursors of B lymphocytes. Pre-B cells from bone marrow of anti-mu treated mice retain their functional integrity, as evidenced by their ability to give rise to sIgM+, LPS-responsive lymphocytes in culture. We also show that cyclophosphamide treatment destroys pre-B cells and that recovery of pre-B cells in bone marrow precedes the regeneration of sIgM+ B lymphocytes. Generation of B lymphocytes in adult mice apparently occurs exclusively in the bone marrow because induction of extramedullary hemopoiesis in spleen was not accompanied by the appearance of pre-B cells in that organ.

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PubMed1977

Ontogeny of Ia and IgD on IgM-bearing B lymphocytes in mice.

We used immunofluorescence to examine the developmental relationship of Ia and IgD on B cells. Pre-B cells in fetal liver did not express Ia. Only very few surface IgM-positive (sIgM+) B cells in fetal spleen were found to be Ia+ and were weakly stained for Ia. After birth there was a linear increase in the proportion of sIgM+ spleen cells which expressed Ia, reaching 95% by 9 days. Adult bone marrow also contains a sizeable proportion of sIgM+ Ia- cells. Unstimulated cells from fetal or newborn liver and spleen expressed Ia at the same rate in culture. Anti-Ia antisera suppressed the LPS-induced differentiation of IgM and IgG plasma cells in cultures of neonatal lymphocytes. Ia was also detected on IgM and IgG plasma cells in vitro suggesting that lipopolysaccharide (LPS)-stimulated B cells by may express Ia antigens, induced by LPS, or appearing as part of normal differentiation. IgD did not appear on sIgM+ cells until 3 days of age and then rose slowly to reach adult levels later than Ia antigens.

Aging↗
PubMed1976

B lymphocyte differentiation induced by lipopolysaccharide. III. Suppression of B cell maturation by anti-mouse immunoglobulin antibodies.

Lipopolysaccharide-(LPS) induced differentiation of mouse B lymphocytes to cells synthesizing large amounts of cytoplasmic IgM and IgG2 could be suppressed by antibodies to mu-chains. Maximal inhibition of LPS-induced differentiation was associated with increased cellular proliferation as measured by incorporation of 3H-thymidine, whereas treatment with anti-mu alone over a wide dosage range did not stimulate cellular proliferation. Spleen cells from newborn mice were suppressed by concentrations of anti-mu several hundred-fold lower than required for adult spleen cells; the adult pattern of susceptibility to suppression was acquired by 1 week of age. No significant differences in susceptibility to anti-mu were found in comparisons of adult spleen, lymph node, bone marrow, and Peyer's patch lymphocytes.

Aging↗
PubMed1976

Relationship between beta2-microglobulin and cell-surface alloantigens of the mouse.

Molecular relationships between beta2m and other cell surface antigens (H-2, Tla, Ia, and Thy-1) were studied with the double immunofluorescence method. Cells were incubated with an antiserum against one antigen capped, and then tested with an antiserum against a second antigen. Capping of beta2m on thymocytes led to simultaneous capping of H-2 and Tla but not Thy-1 antigens; capping of H-2 and TIa (but not Thy-1) antigens resulted in capping of all beta2m detectable by the immunofluorescence method. Similarly, capping of beta2m on B or T lymphocytes resulted in capping of H-2 and vice versa. Ia antigens on B lymphocytes were not capped after the redistribution of beta2m. We conclude from these data that, in the cell membrane of thymocytes, virtually all the beta2m molecules are associated with H-2 and Tla, but not with Thy-1, and that on the cell surface of T or B lymphocytes, virtually all beta2m is associated with H-2 but not with Ia. We found no evidence of any significant free beta2m on either thymocytes or splenocytes.

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PubMed1976

B cell differentiation induced by lipopolysaccharide. IV. Development of immunoglobulin class restriction in precursors of IgG-synthesizing cells.

Direct immunofluorescence was used to determine the classes of immunoglobulins expressed on the surface membrane and in the cytoplasm of newborn and adult B lymphocytes differentiating in response to LPS in vitro. In both newborn and adult spleen, a small proportion of IgM-bearing B lymphocytes also stained for IgG2; adult spleen contained an additional population of lymphocytes bearing IgG2 alone. Combined surface and cytoplasmic staining at intervals after culture initiation and demonstrated both IgM and IgG2 on the membranes of the earliest cells synthesizing cytoplasmic IgG2. At later stages the proportion of IgM-IgG2 surface doubles and of cells synthesizing cytoplasmic IgG2 which had surface IgM fell significantly. Detection of surface IgM on IgG2 precursors correlated with susceptibility of the IgG2 precursors to anti-mu-suppression over the first 3 days in cultures of newborn spleen cells. After 3 days when these cells no longer expressed surface IgM, 2gG2 responses were not suppressed although the IgM response was still inhibited. These results suggest that virgin IgG2 precursors may be B lymphocytes expressing both IgM and IgG2, and that "switching" involves the loss of IgM receptors as these cells proliferate and mature.

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PubMed1975

B lymphocyte differentiation induced by lipopolysaccharide. I. Generation of cells synthesizing four major immunoglobulin classes.

Cultured cells from mouse thoracic duct, spleen, lymph node, Peyer's patches, and bone marrow gave rise to cells containing large amounts of cytoplasmic IgM, IgGl, and IgG2 when stimulated by bacterial lipopolysaccharide (LPS). Differntiation of IgA producers occurred in bone marrow only, and to a lesser extent than other classes. Significant IgM responses preceded development of cells containing other classes. The differentiation of IgG and IgA producers did not appear to depend on T cells, since cultures from nu/nu or thymectomized-irradiated, bone marrow-protected mice responded as well as normals. Cultures from mice rendered deficient in B cells by anti-mu treatment responded normally to T cell mitogens, but did not proliferate or give rise to immunoglobulin-secreting cells when stimulated with LPS. Bone marrow cultures gave relatively meager proliferative responses to LPS, but generated as many or more immunoglobulin-secreting cells as did other tissues.

Animals↗
PubMed1975

B lymphocyte differentiation induced by lipopolysaccharide. II. Response of fetal lymphocytes.

Cultures of mouse fetal liver and spleen, stimulated by bacterial lipopolysaccharide, gave rise to plasma cells staining for IgM, IgG2, IgG1, and IgA. Cells containing Igm and IgG2 were found in cultures from 17-day fetuses, coincident with the appearance of B lymphocytes bearing cell-surface IgM. IgG1- and IgA-containing cells were induced in cultures from 19-day fetuses and 1-day-old mice. The capacity to give rise to immunoglobulin-secreting cells of all classes preceded the development of a significant proliferative response to LPS; the proportions of cells staining for each class reached adult values by 1 day of age whereas the proliferative response did not mature until 3 weeks.

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