The Journal of Experimental Medicine

Tilney, N. L.; Gowans, J. L.

doi: 10.1084/jem.133.5.951pmid: 4928819

Pedicles of skin which lacked a lymphatic drainage were raised on the backs of rats in order to study the importance of afferent lymphatics in sensitization by skin allografts. Although allografts transplanted to the alymphatic pedicles enjoyed a prolonged survival, they contracted progressively from about 3 wk after transplantation and were reduced eventually to small scars. In contrast, autografts survived unchanged in size for the life-span of the pedicles which carried them. The slow contracture of the allografts was associated with sensitization of the host because test allografts applied orthotopically were destroyed with a second-set tempo. No regeneration of lymphatics from the long-standing pedicles could be demonstrated, and it was concluded that sensitization had occurred eventually through the blood, presumably by the process of peripheral sensitization. Allografts on skin pedicles could be destroyed rapidly by active or adoptive immunization, so it is probable that the level of sensitization to which they themselves gave rise was a low one. Although it is not disputed that afferent lymphatics are essential for the rapid destruction of skin allografts, it is clear that the absence of a lymphatic supply does not permanently exempt them from immunological attack in the rat. Footnotes Submitted: 16 October 1970

Klinman, Norman R.

doi: 10.1084/jem.133.5.963pmid: 4101805

The in vitro secondary stimulation of the production of anti-hapten antibody has been analyzed with a view to elucidating the role of the carrier molecule and cell-to-cell interactions in this response. Stimulation was carried out on fragment cultures of the spleens of irradiated BALB/c mice which had been reconstituted with 3–4 x 10 7 spleen cells from isologous mice previously immunized with DNP-Hy. The results indicated that the response was maximized by stimulation with DNP-Hy, the homologous complex, however anti-DNP antibody production could be obtained by stimulation with DNP on several nonhomologous carriers including poly- D -lysine, a poor immunogen. The results also indicated that while DNP-Hy and DNP-nonhomologous-carrier complexes were stimulatory at equally low DNP concentrations, at DNP concentrations over 10 –6 M DNP-Hy was stimulatory, while DNP on nonhomologous carriers was inhibitory. The results are interpreted as indicating that: ( a ) the affinity of the antigen-cell interaction is more likely determined by multivalent binding than by carrier recognition, ( b ) that a stimulatory interaction of a polyvalent antigen with a B-lymphocyte cannot be excluded, ( c ) that if cell-to-cell interaction is necessary for stimulation, then both cells may recognize the same determinant, and ( d ) that the marked enhancement of antigenic stimulation attributable to carrier recognition may result from stimulatory interactions of cells recognizing different antigenic determinants. A mechanism is postulated whereby stimulation is dependent on the formation of stable complexes resulting from two cells sharing in the binding of numerous antigen molecules. Cells recognizing carrier determinants would increase the probability of such interactions particularly at high antigen concentrations. Footnotes Submitted: 17 December 1970

Miller, Harold C.; Cudkowicz, Gustavo

doi: 10.1084/jem.133.5.973pmid: 4928820

Quantitative and qualitative changes of mouse bone marrow cells were studied by limiting dilution assays 2–3.5 months after immunization of donors with sheep erythrocytes or unrelated antigens ( Salmonella typhimurium , horse and chicken erythrocytes). Irradiated (C3H x C57BL/10)F 1 mice were reconstituted with an excess of nonprimed thymocytes and small graded numbers of primed bone marrow cells. Direct and indirect plaque-forming cells (PFC) were induced by secondary stimulation with SRBC and enumerated on the 9th day after cell transplantation. Marrow precursors of PFC (P-PFC) cooperated with thymocytes in the production of direct and indirect PFC after SRBC priming. The limiting dilution plots, which were not compatible with predictions of the Poisson model before immunization, changed and conformed to this model afterwards, as if the population of P-PFC had become functionally more homogeneous. The concentration of marrow P-PFC increased up to the 3rd month after priming, and decreased during the 4th, varying over two logarithms of nucleated marrow cells. The fluctuation was simultaneous and of the same order of magnitude for precursors of direct and indirect PFC, which were class restricted. A third effect of immunization was detected at 3.5 months: individual precursor units generated 3–4 times more direct and indirect PFC than at earlier intervals. Qualitative and quantitative changes of marrow P-PFC participating in anti-sheep responses were specific, since antigens unrelated to SRBC failed to induce them. The data suggested that marrow-derived cells were the major carriers of immunologic memory, but that they functioned in cooperation with thymus-derived inducer cells during secondary anti-sheep responses. Footnotes Submitted: 20 December 1970

Pincus, Carolyn S.; Lamm, Michael E.; Nussenzweig, Victor

doi: 10.1084/jem.133.5.987pmid: 4101806

The ability of passively administered antibody to suppress the immune response against homologous antigenic determinants while concomitantly enhancing the response against other unrelated determinants of the same antigen molecule has been established in two distinct antigen-antibody systems: ( a ) guinea pig γ 2 -immunoglobulin + passive anti-F(ab') 2 antibody, where suppression of anti-F(ab') 2 antibody synthesis is accompanied by enhancement of the anti-Fc response; and ( b ) human secretory IgA + passive anti-serum IgA antibody, where suppression of antibody production against the α and L chains accompanies augmentation of the response to the secretory component. The mechanisms of the suppressive and enhancing effects are probably unrelated for the following reasons: ( a ) Enhancement of the response to certain determinants may be obtained without discernible suppression of the response to the homologous determinants; and ( b ) the F(ab') 2 fragments of passive antibody can mediate immune suppression but were not observed to enhance the response against the unrelated determinants of the same antigen molecule. Also, the timing for achieving maximum suppression or enhancement of antibody formation is not the same; enhancement was obtained only at a later time. Both the enhancement and suppressive effects were obtained with the purified γG fraction of antisera. This finding rules out an exclusive role of γM antibody in the enhancement phenomenon. Footnotes Submitted: 11 January 1971

Natvig, J. B.; Michaelsen, T. E.; Kunkel, H. G.

doi: 10.1084/jem.133.5.1004pmid: 4101803

A survey of a large number of human sera with the heavy chain genetic markers of the γ-globulin system has revealed an unusual gene complex which is inherited as a unit through two different families. The gene complex involves two pairs of γG1 genetic markers which ordinarily behave as homoalleles, Gm z and Gm f for the Fd part of γG1 molecules, and Gm a and non-a for the Fc part. Isolation of the γG1 fraction from the unusual sera demonstrated the presence of the important non-a antigen in the γG1 fraction. Through the use of immunoadsorbents it was shown that these antigens were not part of a single molecule but that separate molecules were involved. The accumulated evidence indicated that the appearance of such homoalleles on the same chromosome probably resulted from a recent gene duplication, giving rise to two γG1 cistrons on one chromosome. Footnotes Submitted: 20 December 1970

Sjöberg, Olof

doi: 10.1084/jem.133.5.1015pmid: 4928815

The number of PFC and of RFC was studied in mice which were unimmunized, immunized, or tolerant against lipopolysaccharide of E. coli 055:B5 origin. The number of PFC/10 6 spleen cells increased from 0.5 in normal to 209 in immunized mice. The corresponding figures for RFC were 93 and 513 RFC/10 6 spleen cells. In tolerant animals, which contained few or no PFC, the number of RFC was increased as compared to that found in unimmunized mice. The formation of rosettes was specific, since their formation was inhibited by soluble coli polysaccharide and by rabbit antisera against mouse immunoglobulins. The antigen-binding cells were not derived from thymus, neither in immune or tolerant mice, because they did not carry the theta antigen. It is suggested that the majority of antigen-binding cells present in tolerant animals are cells having receptors for the antigen of rather low affinity. The relevance of these findings for the induction of high and low zone tolerance is discussed. Footnotes Submitted: 20 December 1970

Cohen, J. John; Claman, Henry N.

doi: 10.1084/jem.133.5.1026pmid: 4928816

Corticosteroids suppress the humoral antibody response of mice to sheep erythrocytes. This response depends on interactions between thymus-derived helper cells and bone marrow-derived antibody-forming cell precursors (AFC precursors). Previous experiments had shown that spleen cells (a mixture of thymus-derived and marrow-derived cells) were sensitive to corticosteroids while AFC precursors in the bone marrow were resistant. The present experiments showed that the thymus of a mouse given 2.5 mg of hydrocortisone acetate, although containing only about 5% of the number of cells of a normal thymus, was as effective as a normal thymus in cooperating with bone marrow when transferred to irradiated syngeneic mice and stimulated with SRBC. The proliferative response of thymus helper cells to SRBC was also resistant to hydrocortisone. In this context, the majority of thymic cells are in the cortex, are rapidly dividing, are sensitive to corticosteroids and are not iminunocompetent. A small number of thymic cells, probably located in the medulla, are resistant to corticosteroids, but are immunocompetent since they can serve as helper cells. The hydrocortisone-sensitive phase of the splenic response to SRBC was found to be the bone marrow-derived AFC precursor since spleens from hydrocortisone-treated donors had immunocompetence restored by normal bone marrow but not by normal thymus cells. Footnotes Submitted: 17 January 1971

Bloth, Björn; Svehag, Sven-Eric

doi: 10.1084/jem.133.5.1035pmid: 4995063

Human colostral IgA and myeloma dimer IgA were purified and examined in the electron microscope using a modified technique of negative staining. Both types of preparation contained double Y-shaped structures of the dimensions: Fab region, 35 x 70 A, and the sum of the two Fc regions, 40 x 140–155 A. Colostral IgA as well as myeloma dimer IgA molecules showed a tendency of bending at the point where the Fc regions joined. Secretory component bound to dimer IgA produced no visible alteration of the molecule. Mild reduction and alkylation of colostral IgA yielded single Y-shaped 7S monomers with the dimensions, Fab, 35 x 70 A, and Fc, 40 x 65–70 A. Footnotes Submitted: 11 January 1971

Kerbel, R. S.; Eidinger, David

doi: 10.1084/jem.133.5.1043pmid: 5554099

A striking correlation between the capacity of an antigen to nonspecifically suppress humoral immune responses of subsequently administered antigens which are non-cross-reacting, i.e. to manifest antigenic competition and produce enlargement of spleen size through cell proliferation, was found. Increase in spleen size was always accompanied by a drop in the normal proportion of thymus-derived cells to non-thymus-derived cells. Various means of altering the immune response to the initial antigen, and hence, the capacity of that antigen to suppress in a model of antigenic competition were performed and correlated with changes in spleen size and in the proportion of θ-positive cells in the spleen. In all instances, when the experimental condition reduced or abolished antigenic competition, the increase in spleen size and reduction in the proportion of θ-positive cells in the spleen was reduced or abolished. Furthermore, under conditions in which the suppressive capacity of the initial antigen was unaltered, the increase in spleen size and reduction in θ-proportion occurred normally. Finally, the better the suppression in a model of antigenic competition, the greater the increase in spleen size and reduction in the proportion of θ-positive cells. On the basis of these observations, it appears that there is a relationship between spleen enlargement through clonally restricted cell proliferation and the expression of antigenic competition; one cannot have the latter without the former. It is postulated that the immunological lesion associated with antigenic competition resides at the level of interference with cell interaction between thymus-derived antigen-reactive cells and marrow-derived antibody-forming cells. This occurs as a result of a relative "diluting out" of cells of both populations carrying antigenic specificity differing from the one(s) which induced the dilution effect in the first place. The net effect of this is to decrease the chance of a "hit" or interaction between a marrow-derived and thymus-derived cell of the same specificities. This mechanism, which is compatible with theories of clonal selection, and which in fact is dependent upon them, supports the view that the term "antigenic competition" is a misnomer; there is no competition by the antigens for anything. The term "antigen-induced suppression" is suggested as a more suitable alternative. Footnotes Submitted: 11 December 1970

Eidinger, David; Ackerman, Aleksander

doi: 10.1084/jem.133.5.1061pmid: 4928817

A cell-transfer system was employed in the present work to investigate several characteristics of the capacity of immune and normal lymphoid cells to transfer the delayed response to methylated human serum albumin in lethally irradiated syngeneic recipients. Spleen cells derived from donor mice immunized with goose erythrocytes were far less effective in transferring responsiveness when compared with equal numbers of normal cells. Statistical analyses indicated a frequency of 1 reactive cell or cell unit in 1.3 x 10 7 normal cells and in 6.2 x 10 7 immune cells. These findings provided confirmatory evidence that antigen-induced suppression (antigenic competition) employing sequential administration of two non-cross-reacting antigens is due to relative deficits of immunocompetent cells generated by lymphoproliferation in lymphoid tissues secondary to immunization with the initial antigen. The cellular deficit in the immune population was shown to be resident in a thymus cell population, which restored the number of responders to a level equivalent to the normal population. The thymic cell was akin to the antigen-reactive cell. The cell limiting the degree of response, that is the effector cell for both normal and immune cell populations, was of bone marrow origin. Both populations of cells were shown to act in synergy to reconstitute the delayed response to the antigen. Footnotes Submitted: 16 December 1970