The Reaction of 2,4-Dinitrobenzenesulfonic Acid with Free Amino Groups of Proteins

105

In the system studied, antigenic competition between two haptenic determinants was found to be of the same extent whether the haptens were on the same or on separate carrier molecules. Suppression of antibody formation to one determinant by administration of passive antibody partially eliminated the depressive effects of antigenic competition when the two haptens were located on separate carrier molecules but had no effect on antibody production to the second hapten when the two determinants were present on the same molecule. The results are discussed in terms of the mechanisms of suppression, antigenic competition, and control of antibody formation.

Section: Methodsmentioning

confidence: 99%

Studies on the Control of Antibody Synthesis

Brody

Walker

Siskind

1967

105

“…Bovine serum albumin (BSA) and bovine gamma globulin (BGG) were obtained from the Nutritional Biochemical Corporation, Cleveland, Ohio. They were coupled with 2,4-dinitrophenyl (DNP) hapten by the method of Eisen et al (16). The following DNP conjugates were used in the present studies: DNP730-KLH (assuming average tool wt of KLH as 7,000,000), DNP~-BGG and DNP34-BSA.…”

mentioning

confidence: 99%

Selective Roles of Thymus-Derived Lymphocytes in the Antibody Response

Tada

Takemori

1974

It is rapidly becoming clear that in certain antibody responses thymus-derived lymphocytes (T cells) are definitely endowed with a role to suppress responses of bone marrow-derived lymphocytes (B cells) to antigen (1-12). Such inhibitory effect of T cells led to a designation of "suppressor T cell" and is being recognized in large measure as an important regulatory device in various antibody responses. Some forms of immunological tolerance are also explained by the active suppression by T cells rather than the elimination of B-cell clones (12)(13)(14).The suppression by T cells has been shown to be mediated by both antigenspecific and nonspeclfiC mechanisms, while both pathways may be equally important for the regulation of antibody synthesis. Our previous studies (3) demonstrated that T cells primed with a carrier antigen suppressed an ongoing IgE antibody synthesis by B cells against a hapten coupled to the same carrier; thus this suppression appeared to be antigen-specific. The presence of a subcellular component of T cells that specifically suppresses the B-cell response was also reported (15).Our more recent studies on the specific suppression of IgM antibody response by T cells (11) showed another important fact, namely, that the T cell's suppressive effect on B cells varied depending on the time when the suppressor cells were given to the immunized recipients. The suppressor effect on the IgM antibody response was found to be more pronounced if the primed T cells were given to the recipients at a time when antibody-forming cells were starting to appear in their spleen rather than at the time of immunization. These observations suggest that the susceptibility of B cells to the suppressive effect of T cells is inherently different depending on the maturation stage of B cells and on the immunoglobulin classes which they are destined to produce. The present experiments were undertaken to study the mode and sites of action of suppressor T cells on antibody response in mice with special reference to the differential effect of T cells on B cells which produce IgM and IgG antibodies.

“…Dinitrophenylated bovine serum albumin (DNP-BSA)' and N-2,4-dinitrophenyl-Eamino-N-caproic acid (DNP-EACA) were prepared as previously described (5,8) . There were approximately 23 DNP groups per molecule of DNP-BSA based upon its absorbancy at 360 nm when e=17,500 for DNP-lysine .…”

mentioning

confidence: 99%

Binding of antigen by immunocytes. II. Effect of specific Ig on antigen binding by MOPC 315 cells.

Bystryn¹,

Siskind²,

Uhr³

1975

Antibody has been postulated to regulate its production through a feedback mechanism, which modulates the amount of antigen available in immunogenic form (1). However, new antibody synthesis may occur even in the presence of a large excess of circulating antibody, e.g., after secondary immunization or after reduction of serum antibody levels by exchange transfusion or immunoadsorbants (2-4) . Since stimulation of B cells to antibody-secreting cells requires the interaction of antigen with specific cell surface binding sites, these findings suggest that immune cells are able to capture antigen even in the presence of a large excess of antibody .Earlier studies have demonstrated that cells of the murine plasmacytoma MOPC 315 have surface immunoglobulin (Ig) with specificity for DNP (5) and also secrete into the serum of animals bearing this tumor an IgA which binds DNP with moderate affinity (6, 7) . Thus MOPC 315 cells are analogous to normal B cells in having on their surface Ig which will specifically bind antigen. We have used DNP conjugates and MOPC 315 cells as a model system to study the energetics of interaction of antigen with specific binding sites on immunocytes (5) .In the present report this system has been used to examine the ability of cells to compete with free antibody for antigen. The binding of radiolabeled multivalent and univalent DNP conjugates to MOPC 315 cells was measured in the presence of various concentrations of serum obtained from mice bearing this tumor . The data reported here indicate that free specific Ig will compete with cell surface binding sites for antigen, and that binding of a multivalent conjugate to cells is favored over its binding to Ig. Thus, immunocytes can effectively interact with, and specifically bind, antigen even in the presence of a large excess of free Ig of similar specificity. Materials and MethodsSource and Preparation of Cells. The murine plasmacytomas, MOPC 315