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J M Teale

Publications and source records attributed to J M Teale.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of fetal exposure to ultrasound on B lymphocyte function and antibody class production.

The purpose of this study was to determine if ultrasound radiation would affect the ability of antigen-stimulated B cells and their clonal progeny to undergo the isotype switch and produce diverse antibody classes. Pregnant BALB/c mice were exposed to various intensities of ultrasound (0.1-3.0 W/cm2) at different ages of gestation. Spleens from the resulting offspring were removed five or ten days after birth. The splenocytes were analyzed for the frequency of B cells capable of responding to the hapten 2,4 dinitrophenyl (DNP) using the splenic fragment assay, a B cell cloning assay. The DNP-responsive B cell clones were then classified on the basis of isotype expression. It was found that ultrasonic radiation during gestation did not alter the frequency of B cells responding to DNP. Furthermore, ultrasound had no apparent effect on the B lymphocyte's capacity to switch to different isotypes after antigenic stimulation. Thus, the results indicate that prenatal exposure to ultrasound does not appreciably affect the genetic and cellular processes necessary for the isotype switch and antibody class production.

2,4-Dinitrophenol↗
PubMed1988

Comparison of the fetal and adult functional B cell repertoires by analysis of VH gene family expression.

The functional B cell repertoire in BALB/c mice was assessed at various stages in ontogeny. This was done by analyzing VH gene family expression using the sensitive technique of in situ hybridization. The B cell repertoire was probed with the mitogen, LPS, and the antigen DNP. DNP was chosen because B cells responsive to this hapten appear very early in ontogeny. The APCs that developed after stimulation with LPS or DNP were analyzed for VH gene expression by in situ hybridization of individual cells using radiolabeled VH gene family probes. The results indicated that VH gene expression in fetal B cells after stimulation was distinct from adult B cells in that there was a biased expression of D proximal families. The results indicated that this bias was associated with developmental age and not a given differentiation stage in the B cell lineage. In addition, stimulation of fetal B cells with DNP resulted in a large increase in expression of member(s) of VH 36-60, suggesting that the early appearance of DNP-responsive B cells is not strictly correlated with preferential rearrangement of D proximal families, VH 7183 and VH Q52. However, the results suggested that a large proportion of pre-B cells that preferentially rearrange D proximal families early in ontogeny become part of the functional developing repertoire.

Aging↗
PubMed1988

Strain-dependent expression of VH gene families.

The tremendous diversity of the antibody specificity repertoire stems from the ability of each developing B cell to select one out of many possible variable, diversity, and joining gene segments by specific rearrangement of the DNA. The mechanism by which V region gene segments is selected is not known. Moreover, evidence for both random and nonrandom expression of VH genes in mature B cells has been presented previously. In this report, the technique of in situ hybridization is used to accurately measure at the single cell level VH gene family expression in LPS-induced cells from several strains. In this way, at least one-third of the B cells are stimulated and a large sampling of activated splenocytes from each strain analyzed. The use of in situ hybridization eliminates any potential biases resulting from transformation protocols. In addition, because all populations of cells are analyzed by both in situ hybridization and immunocytochemical staining with anti-IgM, the proportion of cells detected by in situ hybridization could be compared with the proportion of B cells, blasts, and plasma cells in the population. It was concluded from these comparisons that the cells being detected by in situ hybridization under the conditions described are plasmablasts and plasma cells. Therefore, an accurate measure of the functional and expressed VH gene repertoire could be made. The results clearly demonstrate strain-dependent variation in VH gene family expression, particularly VH 7183 and VH J558 with up to three-fold differences observed. Thus, either there is considerable strain variation in the number of functional VH gene family segments or the expression of VH genes is not entirely random.

Animals↗
PubMed1988

Effect of growth and differentiation stimuli on the development of antigen-responsive B cells in fetal liver.

The development of the B cell immune repertoire was studied using an in vitro fetal organ culture system. In order to analyze the mechanism by which B cell precursors clonally expand and diversify, fetal lymphoid tissues were incubated in the presence of several factors known to influence B cell differentiation: IL-1, IL-2, WEHI-3 culture supernatant containing IL-3, and a factor from a cyclic neutropenia patient (CNF). By analyzing the effect of exogenous factors on the frequency of antigen-responsive B cells, the ability of the factor to either inhibit or enhance clonal expansion was determined. It was found that the addition of IL-1, WEHI-3 supernatant, or CNF increased the frequency of DNP-responsive B cells suggesting an enhancement of clonal expansion. IL-2, on the other hand, did not alter the frequency of antigen-responsive B cells. The effect of added factors on the kinetics of appearance of phosphorylcholine (PC)-responsive B cells, which are known to be acquired in ontogeny about 2 weeks later than DNP-responsive B cells, was also analyzed. The data indicate that CNF, unlike IL-1, IL-2, and WEHI-3 culture supernatant, results in an earlier appearance of PC-responsive B cells. These results suggest that soluble factors may play a role in the generation of the B cell repertoire.

Animals↗
PubMed1987

The contribution of parasite-specific T cells to isotype restriction in Mesocestoides corti-infected mice.

Mice infected with the parasite Mesocestoides corti undergo a polyclonal antibody response that results in a hypergammaglobulinemia restricted to the IgM and IgG1 isotypes. It was found that a similar restriction to IgM and IgG1 could be observed in an in vitro lymphocyte culture system providing that the source of helper T cells was from infected animals. In order to characterize the helper T cells responsible for the restriction, helper T cell clones were generated. Attempts to obtain isotype-restricting helper T cell clones by using the intact, nonviable organism were unsuccessful in that these T cell clones promoted multiple antibody class expression. However, two types of CD4+ (cluster designation) T cell clones were generated by cultivation on the live organism that appeared relevant to the observed restriction. These T cells did not function as conventional carrier-specific helper T cells. Instead, they were shown to regulate T-dependent responses to 2,4-dinitrophenyl-keyhole limpet hemocyanin by 2,4-dinitrophenyl-specific B cells and keyhole limpet hemocyanin-primed T cells derived from uninfected mice. The helper phenotype of one regulatory clone enhanced the IgG1 response, whereas the other phenotype inhibited the production of the other non-IgM isotypes tested. It is concluded that the activities of these two prototype regulatory T cell clones may predominate in infected animals resulting in the IgM, IgG1 dominance of the antibody response.

Animals↗
PubMed1987

Isotype restriction during infection of mice with the cestode Mesocestoides corti: role of immune suppression.

Mice infected with the parasite Mesocestoides corti produce a vigorous antibody response that is restricted to the IgM and IgG1 heavy chain classes. The isotypic restriction observed is apparently associated with active infection and is not a unique characteristic of responses to M. corti antigens. Thus, animals immunized with intact but nonviable parasites respond with the production of a variety of antibody isotypes in addition to IgM and IgG1. To delineate immunoregulatory mechanisms involved in the isotypic restriction of antibody responses to M. corti, an in vitro lymphocyte suspension culture was established. The data indicate that there are two cell subsets in the spleens of infected mice that contribute to an overall suppression of the in vitro antibody response. Thus, both Lyt-2+ cells and G-10-adherent cells must be removed to maximize antibody production. However, the anti-parasite response obtained in vitro after depletion of Lyt-2+ cells and G-10-adherent cells is restricted to the IgM and IgG1 isotypes as observed in vivo, indicating that suppression is not actively involved in the IgM, IgG1 dominance of the response. The cellular regulation associated with this restriction was then studied by using isolated helper T cells derived from parasite-infected animals to stimulate B cells from uninfected animals. The antibody produced was again restricted to IgM and IgG1, indicating that the helper T cells were regulating the preferential expression of the IgM and IgG1 antibody classes.

Animals↗
PubMed1986

Influence of immunoglobulin-dependent T cells on antibody class switching.

Normal and B cell-deficient, carrier-primed mice were irradiated and were adoptively transferred with B cells to evaluate the role of putative Ig- and B cell-dependent T cells in anti-hapten antibody responses. The response was analyzed by using the splenic focus assay, which allowed us to examine the frequency of responding B cells and the production of multiple isotypes by single precursor B cells. This analysis revealed that both primary and secondary B cells were activated at higher frequency in the spleens of normal recipients, and production of isotypes other than IgM and IgG1 was enhanced in normal recipients as compared with anti-mu-treated recipients. Both changes could be restored to control levels by co-transfer of T cells from normal donors primed with an unrelated carrier, provided the free carrier was added to the assay culture. These results are consistent with a role for Ig or B cell-dependent helper T cells in the optimal activation and the resulting isotype expression of both primary and secondary B cells.

Animals↗
PubMed1986

Surface IgG-bearing cells retain the capacity to secrete IgM.

Our previous studies indicated that a large proportion of surface IgG+-primed B cells give rise to clones secreting IgM antibodies. Due to the implications of this result relative to molecular mechanisms of class switching, it was important to document that the surface IgG had been endogenously synthesized by the surface IgG+ cells and was not present as a result of cytophilic IgG. Therefore, spleen cells from immunized mice were treated sequentially with anti-immunoglobulin and protease which removed greater than 99% of surface immunoglobulin. After overnight incubation to allow resynthesis of surface immunoglobulin, the treated cells were sorted for surface IgG-bearing cells and were transferred to carrier-primed, irradiated adoptive recipients for analysis in the splenic focus assay. It was found that the majority of antibody-secreting clones derived from these surface IgG+ B cells still synthesized IgM. These data are discussed relative to current concepts of molecular mechanisms of immunoglobulin class switching.

Animals↗
PubMed1986

Clonotypic analysis of the fetal B cell repertoire: evidence for an early and predominant expression of idiotypes associated with the VH 36-60 family.

Determining the mechanisms by which B cells develop that culminates in the generation of a diverse repertoire is critical to our understanding of how the immune response is regulated. The B cell specificity repertoire appears to be developmentally acquired in a predetermined, temporally ordered fashion. Thus, in the Balb/c mouse, the ontogenetic appearance of functional B cells specific for various hapten probes occurs in the order of dinitrophenol (DNP), fluorescein (Fl), and phosphorylcholine (PC). In addition, when the influenza virus hemagglutinin molecule was used as an antigen probe, similar conclusions were drawn regarding a patterned acquisition of the specificity repertoire. More recently, we have used a fetal organ culture system to show that hapten-responsive B cells appear in the same predictable, temporal order in vitro. The importance of these studies was that the effects of environmental influences were minimized in the absence of circulation and cell migration, and therefore the results indicated that the patterned emergence of the specificity repertoire observed was largely the result of genetic regulatory processes. Recent molecular findings may relate to such genetic regulatory processes. The VH genes in Balb/c mice have been grouped into eight families based on sequence homology, and have been mapped relative to the constant region genes. Yancopoulos et al. and Perlmutter et al. have shown that the VH gene segments closest to the JH cluster, the VH1B 7183 family, are preferentially utilized in transformed fetal pre-B cell lines and in fetal B cell hybridomas. This led to the hypothesis that the developmental control of the expression of VH gene segments is related to chromosomal organization. A logical extension of these findings is that the programmed appearance of particular clonotypes in ontogeny may be explained, in part, by the preferential use of particular VH gene segments. However, to what extent the transformed B cell lines represent members of the functional expressed repertoire could not be evaluated. In the studies described herein, the fetal organ culture system was used to assess the early expressed repertoire at the clonotypic level using idiotypic analysis. Anti-DNP secreting clones were derived from fetal organ cultures and tested for the presence of two idiotypes, 36 and MOPC 460 (460). The 36 idiotype is a predominant DNP clonotype of the neonatal repertoire, while the 460 idiotype is a major cross-reactive idiotype of the adult DNP response.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Tolerance and B cell repertoire establishment.

We have probed the mechanism by which immature B cells are uniquely susceptible to antigen-induced inactivation. Our studies have demonstrated that this tolerance trigger is an active process that requires both energy metabolism and the biosynthesis of various macromolecules, including protein, RNA, and DNA. However, the tolerance trigger is resistant to inhibitors of patching and capping, as well as an inhibitor of mitosis. The tolerance trigger requires a high-affinity interaction between a multivalent antigen and the cells' Ig receptor, but apparently does not require interactions with other cell surface molecules, or interactions with T cells or macrophages. Our efforts to demonstrate the physiological applicability of this tolerance trigger have concentrated on an attempt to demonstrate potentially self-reactive cells within the immature bone marrow population that do not appear in the mature splenic B cell population. To date we have identified prereceptor B cells of several specificities whose frequency is much lower in the spleen and whose elimination appears to involve tolerance rather than antiidiotypic regulation. However, the demonstration that such cells are eliminated by contact with self-antigens has not as yet been accomplished.

2,4-Dinitrophenol↗
PubMed1985

B cell immune repertoire diversifies in a predictable temporal order in vitro.

The appearance of functional, antigen-specific B cells was studied in an in vitro fetal organ culture system in the absence of environmental influences associated with circulation and cell migration. In this way the B cell diversification process could be analyzed when genetic influences were dominating. By using this system in combination with the splenic focus assay, the frequency of developing B cells responsive to a number of hapten probes was measured. The results indicate that B cell diversification in vitro, in the apparent absence of many environmental influences, results in the appearance of antigen-responsive B cells in a predictable, temporal order. The results suggest that the acquisition of the expressed repertoire to a large extent is genetically controlled.

Animals↗
PubMed1984

Membrane and metabolic requirements for tolerance induction of neonatal B cells.

The metabolic requirements of tolerance induction of immature B cells has been analyzed through the use of various putative inhibitors. The study utilizes the splenic fragment assay in which tolerance induction of individual B cells can be examined. Concentrations of inhibitors were determined which, if removed after the first 18 hr of culture, before antigenic stimulation, had no inhibitory effects. Thus, by adding tolerogen in the presence or absence of inhibitor during the first 18 hr of culture, the effect of that inhibitor on tolerance could be assessed. By using this protocol, the data indicate that several metabolic functions of the cell are necessary for tolerance induction to occur, including RNA biosynthesis, DNA biosynthesis, and a methyltransferase reaction, because drugs that interfere with these metabolic processes also prevent tolerance induction. Our previous studies indicated that protein biosynthesis and energy generation are also required. However, drugs that interact with the cytoskeletal structure of the cell and inhibit surface immunoglobulin capping do not interfere with tolerance induction. Moreover, colchicine, which inhibits cell division, does not inhibit B cell tolerance. Collectively, the results provide compelling evidence that the mechanism of immature B cell tolerance involves an active process requiring several metabolic activities of the cell.

Animals↗
PubMed1983

The use of specific helper T cell clones to study the regulation of isotype expression by antigen-stimulated B cell clones.

In order to determine the mechanism by which helper T cells regulate the production of the various immunoglobulin (Ig) classes, a number of helper T cell clones specific for keyhole limpet hemocyanin (KLH) were generated. These helper T cell clones then were used in a modified splenic fragment system whereby cloned helper T cells and a source of B cells were limit-diluted into naive, lethally irradiated recipients. The B cell clones that were subsequently stimulated in such an assay system by the addition of the antigen 2,4-dinitrophenol (DNP)-KLH then were tested for the various isotypes produced. The results of these studies indicate that the use of a single helper T cell clone could result in the production of all known Ig isotypes including IgE. Moreover, the use of a single helper T cell clone could result in multiple isotype production by a single B cell clone. However, a comparison of the isotypes secreted by a number of different B cell clones that were stimulated with the same helper T cell clone indicated that a variety of isotypic patterns could be obtained. In addition, it was found that the majority of B cell clones produced in the presence of T cell clones secrete fewer numbers of different isotypes compared with B cell clones generated with a heterogeneous population of T cells. Finally, no evidence could be found for isotype-specific helper T cell clones, although a few of the T cell clones appeared to induce a somewhat restricted isotype pattern in which only two or three different isotypes were observed.

Animals↗
PubMed1982

The potential of B lymphocytes for isotype expression.

The isotypes secreted by the progeny of individual antigenically stimulated murine B cells were studied to determine the extent to which B cells exhibit class commitment. The study includes an analysis of B lymphocytes at different maturational states as well as an analysis of B cells selected on the basis of their surface isotype. All B cell subsets were analyzed under optimal stimulation conditions by the T-dependent splenic focus assay. From these studies it was found that the majority of B cells are not committed to a particular isotype that on antigenic stimulation would give rise to all progeny that secrete solely the one immunoglobulin class. The results indicate that the major influence attributable to the B cells themselves with regard to isotype commitment stems from the maturational state of the B cell. Thus, immature B cells from fetal liver and spleen give rise to clones secreting IgM and/or IgA, but not IgG; secondary B cells that lack surface mu appear unable to produce IgM-secreting clones on stimulation. However, most mature B cells (both primary and secondary) have the potential to give rise to clones secreting multiple immunoglobulin classes including IgE. Therefore, the predominant form of regulation regarding isotype expression is more likely to be controlled at the T cell level rather than separate lineages of B cells committed to a particular isotype prior to antigenic exposure.

Animals↗
PubMed1981

A clonal analysis of the IgE response and its implications with regard to isotope commitment.

In a clonal analysis of the IgE response, it was found that a small proportion of primary or nonimmune B cells in spleen and mesenteric lymph nodes can be stimulated by antigen to produce IgE-secreting clones. In addition, there appears to be no substantial difference in the frequency of such cells between the classical low and high IgE responder strains. An analysis of immune, or memory, B cells revealed substantial increases in the frequency of B cells secreting IgE as compared with primary B cells, although the actual proportion of B cells secreting IgE remained relatively low. When the IgE-secreting clones derived from either primary or secondary B cells were reanalyzed for the presence of other isotypes, it was found that all clones secreting IgE were secreting at least one other isotype, with the majority secreting two or three other isotypes in addition to IgE. This demonstrates that there is no distinct subpopulation of B cells committed to IgE expression per se.

Animals↗
PubMed1981

Immunoglobulin class commitment exhibited by B lymphocytes separated according to surface isotype.

In order to determine the extent to which B cells exhibit class commitment, the isotype(s) secreted by individual B cells and their progeny was studied in relation to the isotype(s) expressed on the surface of the B cell. Both primary and secondary B cells were separated according to cell surface isotypes and analyzed under optimal stimulation conditions using the T-dependent splenic focus assay. From these studies the following conclusions conclude be made: a) essentially all mature primary B cells appear to express mu on their surface; b) accordingly, the primary B cell population appears to be devoid of B cells expressing solely IgG on their surface; c) the majority of primary B cells in the presence of optimal T cell help have the potential for multiple class production; d) the secretion of IgA coincides with that of IgM and not IgG in its synthesis by immature B cells; e) a substantial proportion of memory B cells bear mu on their surface; f) memory B cells that lack s-mu are unable to yield clones secreting IgM; and g) a substantial proportion of memory B cells have the potential for multiple class production.

Animals↗