The Mechanism of Antigenic Stimulation of Primary and Secondary Clonal Precursor Cells

109

The process by which an individual's repertoire of unique antibody-forming cell precursor (B-cell)' specificities (clonotypes) is acquired has been the subject of extensive investigation and controversy over the past several years (1-3) . To help clarify the mechanism by which diversification of B-cell clonotypes might occur, this laboratory has conducted an investigation of the B-cell clonotypes available during the early stages of neonatal development, i .e ., at an important period in the initial development of the specificity repertoire .Previous reports from this laboratory have demonstrated that the adoptive transfer of neonatal spleen cells to an adult, carrier-primed environment maximizes the responsiveness of neonatal B cells (4-6) . The principle rationale for this approach-that neonatal B cells are indeed immunologically competent when provided with ancillary mechanisms by the adult host environment-has been verified by other investigators (7,8) . Previous analyses from this laboratory have also shown the similarity of neonatal and adult primary B cells, in terms of the kinetics and antigen dose dependence of the antibody response (4), and the relative ease of hapten inhibition of primary B-cell stimulation (6,9,10) . Recently, an analysis of the frequency of neonatal B-cell precursors specific for the haptenic determinants 2,4-dinitrophenyl (DNP) ; 2,4,6-trinitrophenyl (TNP) ; and fluorescein (FL) has demonstrated that a disparity exists in the rate of development of FL-specific precursor cells, as compared to DNP-or TNP-specific cells (5) . Thus, at an early stage in the generation of specificity, when the total number of available specificities is limited, significant disparities may exist due to potential "all or none" expressions .This report extends these observations by an analysis of the clonotypes available in neonatal BALB/c mice which are specific for the DNP and TNP haptenic *

“…The methodology for in vitro B-cell cloning and the detection of positive fragment cultures by radioimmunoassay has been described previously (4,9) .…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

The characterization fo the B-cell repertoire specific for the 2,4-dinitrophenyl and 2,4,6-trinitrophenyl determinants in neonatal BALB/c mice.

Klinman¹,

Press²

1975

109

“…Previous studies from this laboratory have demonstrated that the splenic focus technique permits detectable stimulation of individual neonatal or adult clonal precursor cells (28)(29)(30)(31)(32). Since tolerogens can be added to fragment cultures and removed before stimulation, this system provides a unique opportunity to compare the interaction of tolerogen with individual neonatal and adult cells.…”

mentioning

confidence: 99%

In vitro tolerance induction of neonatal murine B cells.

Metcalf¹,

Klinman²

1976

263

149

Immunologic tolerance was originally defined as specific hyporesponsiveness to an antigen which results from prior contact with that antigen (1, 2). The concept of natural tolerance to self-antigens was perceived by Burnet (3) as the deletion of clones reactive to autologous antigens after contact of these antigens with the reactive cells' specific antigen receptors during the development of the cell's immunologic competence. If such a theory were to have physiological relevance, then several predictions should be realized: (a) developing cells should be significantly more susceptible to tolerance induction than their mature counterparts; (b) tolerance should be inducible over a wide range of antigen concentrations, since the concentrations of different self-antigens present presumably vary; (c) since the spectrum of self-antigens is diverse, the development of unresponsiveness should be plausible with a wide variety of antigenic structures; (d) since bone marrow-derived precursors to antibody-forming cells (B cells) presumably mature independently of other cell types, induction of B-cell tolerance should occur in the absence of antigen-specific thymus-derived lymphocytes (T cells); (e) the discrimination between self and nonself would be absolute, and therefore, tolerance should exhibit exquisite determinant specificity.

“…This constraint has recently been removed through B-cell cloning assays, in particular, the in vitro splenic focus assay developed by Klinman and Press (10,11) in which the adult splenic environment is provided complete with carrier-primed T cells, thus facilitating the measurement of B-cell precursors in fetal and neonatal tissues. It is, therefore, of great interest to combine the technique of organ culture with this sensitive B-cell cloning assay to study the differentiation of B cells in relation to immune reactivity.…”

mentioning

confidence: 99%

Ontogenic development of B-lymphocyte function and tolerance susceptibility in vivo and in an in vitro organ culture system.

Teale¹,

Mandel²

1980

The study of the development of B cells in the various lymphoid tissues in vivo is complicated by factors relating to cell migration. An in vitro organ culture system provides an opportunity for analyzing the differentiation of B lymphocytes in a closed system without the complication of cell migration. Moreover, it is possible to manipulate the experimental conditions in vitro in an attempt to alter the development of B cells and learn more about the process. One such manipulation is the addition of a tolerogen (e.g., a hapten protein conjugate) to the culture medium to study its effect on the development of hapten specific B cells.It has previously been shown that some in vitro systems can support the growth and differentiation of fetal lymphoid tissues. 6-8). Thus, the majority of studies with fetal tissues, particularly in vitro studies, have followed Bcell differentiation by the acquisition of mitogen reactivity, the development of antigen binding cells, or the acquisition of s-Ig. Although these markers do indeed reflect the maturation of B cells, they do not address the most important aspect of the B cell, namely the production of antibody to a specific antigen.In the past it has been very difficult to study the specific responses of fetal lymphoid cells or even neonatal cells because of the small number of B cells present for a