Detection of Simultaneous Antibody Synthesis in Plasma Cells and Specialized Lymphocytes in Rabbit Lymph Nodes

A preceding paper described the ultrastructure of antibody-forming cells of mice and rabbits studied in considerable numbers (1). In confirmation of previous studies from this and other laboratories, it was shown that lymphocytes and plasmacytes in various stages of differentiation contributed to the heterogeneity of the antibody-producing cells (2-8). Morphological forms suggesting transition between cells of the lymphocytic and of the plasmacytic series were also described (1). A comparison of cells forming rosettes with those producing plaques showed that the rosette-forming cells (RFC)I were largely in the lymphocytic series, whereas the plaque-forming cells (PFC) were largely plasmacytic (1).For further study of antibody-producing cells, especially in the early stages of proliferation and antibody release, RFC were chosen, since the number of rosettes produced by a given suspension of antibody-producing cells is many times the number of plaques, so that rosette formation would clearly provide the more sensitive technic. In the present study the kinetics of antibody-forming cells was studied both in terms of the numbers of RFC and of uptake of radioactive label. Cells were obtained from antibody-producing spleens of mice and lymph nodes of rabbits, at various intervals after a first or second injection of antigen, for determination of frequency of RFC and of RFC which could be

supporting

confidence: 71%

Studies on Antibody-Producing Cells

Gudat

Harris

et al. 1971

“…These different cell types increase at similar rates during the exponential phase of the response, suggesting their interdependence (53). Moreover, a morphological transition between lymphocytic and plasmocytic series has also been described (16,61). Recently, the derivation of plasma cells from small lymphocytes has been demonstrated unequivocally (62,63).…”

Section: Discussionmentioning

confidence: 99%

Cytodynamics of the Immune Response in Two Lines of Mice Genetically Selected for "High" and "Low" Antibody Synthesis

Biozzi

Stiffel

Mouton

et al. 1972

Two lines of mice have been separated by selective breeding for the character "agglutinin production to heterologous erythrocytes." Around the 18th generation of selection the two lines could be considered as homozygous for the character investigated. This trait is under the control of a group of additive genes. The interline difference in the production of anti-SE agglutinins was verified for the range of antigen doses from subimmunogenic to maximal. After intravenous immunization with an optimal dose of SE, the duration of the exponential rise in serum antibody was 4–5 days in both lines. At this time most of the interline difference in responsiveness is already expressed. A cytodynamic study carried out in terms of plaque-forming cells (PFC) and rosette-forming cells (RFC) in the spleen during the exponential phase showed that the principal interline difference is found in the doubling time of cells engaged in the immune response. More precise cytodynamic analysis made in terms of RFC showed that the doubling time of RFC is 9 hr in high responder and 16 hr in low responder mice. The duration of the exponential rise and the number of target cells stimulated by antigen is the same in both lines. The interline difference at the end of the exponential rise (4 days postimmunization) is larger in terms of serum antibody (30–40-fold) than in terms of PFC or RFC (20- and 11-fold, respectively). A morphological study of RFC in nonimmunized mice showed that about 90% of rosettes were formed by small lymphocytes in both lines. The remainder were medium-sized lymphocytes. At the peak of the cellular response the RFC have differentiated into large lymphocytes, blast cells, and plasma cells. The contribution of plasma cells to RFC is much greater in the high than in the low line. The cytodynamic and morphologic results presented in this article are compatible with the hypothesis that the group of genes segregated in each line during the selective breeding control and regulate the rate of multiplication and differentiation of the antibody-producing cells.

“…11 A illustrates a model in which the cell surface is the last step in an ordered transport sequence: (a) intracellular transport of Ig occurs only within vesicles, (b) in the post-Golgi vesicle, a small proportion of Ig remains attached to the membrane, whereas the vast majority of Ig is free within the vesicle; the proportion of bound to free Ig is higher for IgM than for IgG, (c) the vesicle fuses with the plasma membrane, (d) reverse pinocytosis exteriorizes the Ig; the majority is immediately released "free," (including virtually all of the IgG), (e) the cell surface Ig (the attached IgM) is released as a function of time and perhaps as a fragment of plasma membrane. It is uncertain whether shedding is analogous to the type of clasmacytosis postulated to occur in plasma cells by Avrameas and Leduc (38). Retrieval of plasma membrane may occur through pinocytosis and "shuttle" of empty vesicles as has been postulated for secretory cells in which there is a duct system (39).…”

Section: Release Of Cell Surface Ig By Small Lymphocytes--when Surfamentioning

confidence: 94%

Cell Surface Immunoglobulin

Vitetta

Uhr

1972

108

Turnover and release of cell surface Ig and secretion of total intracellular Ig has been studied in small lymphocytes from normal mouse spleen. The major findings to emerge are: (a) small lymphocytes secrete 8S IgM and IgG. A small portion of the 8S IgM, but virtually none of the IgG appears to have a cell surface phase. (b) Cell surface IgM is actively turned over with a half-life of 6–8 hr, and turnover can be accounted for by release into the incubation medium. Release is temperature dependent. (c) Released cell surface Ig is noncovalently bound to a fragment of plasma membrane. (d) H-2 antigens are not released during short-term incubation. Based on the above findings, we propose a model for the transport and release of both cell surface and conventionally secreted Ig.