bluuebunny/crossref_metadata_2025 huggingface dataset:
The emigration of lymphocytes from Peyer's patches in sheep
Authors: Reynolds John D. , Pabst Reinhard
Published: February 2007

The magnitude of the output of lymphocytes from Peyer's patches (PP), the morphology of the lymphocytes and their route of exit from PP has been examined in sheep. An extracorporeal perfusion system was used to selectively label a 3–4 m length of the terminal ileum of lambs at 6–10 weeks of age (the mesenteric lymph nodes had previously been excised from most lambs). This part of the intestine contains about 80% of the total PP tissue in a lamb and most of the lymphoid cells in the perfused tissue were within the PP. During a 10 min labeling period, fluorescein isothiocyanate (FITC) was added to the perfusate to label all the cells in the perfused tissues and [3H]thymidine ([3H] dThd) was added at the same time to label only those cells in the S‐phase of the cell cycle. The unincorporated label was then washed from the perfused tissues, the normal blood circulation was reestablished and the lamb allowed to recover from anesthesia. It was established that the labeling was restricted to the perfused tissue and therefore that any labeled cells subsequently found elsewhere in the animal must have emigrated from the terminal ileum. During the 24 h after perfusion 1.4 × 109−3.9 × 109 lymphoid cells (i.e. FITC labeled) left the perfused tissues via the lymph; 12–19% of these cells were either in the process of dividing or less than 24 h old (i.e. [3H] dThd labeled). The majority of the labeled cells probably came from the PP and most were classified as small lymphocytes although the [3H] dThd labeled population included a high proportion of large lymphocyte and lymphoblasts especially during the early hours after the perfusion. The labeled lymphocytes entered the blood in substantial numbers which increased linearly with time so that by 24 h about 7% of the lymphocytes in the blood were fluorescent. The numbers of newly produced cells began to increase rapidly in the blood only during the 12 h to 24 h period. The number of labeled cells in the blood was reduced by about 95% when the lymph from the perfused tissues was drained from the lamb during the experiment. This result provides clear evidence that the vast majority of all of the cells that leave the PP do so via the lymph and not via the blood.
Different mechanisms of release of vasoactive amines by mast cells occur in T cell‐dependent compared to IgE‐dependent cutaneous hypersensitivity responses
Authors: van Loveren Henk , Kraeuter‐Kops Sandra , Askenase Philip W.
Published: February 2007

It has recently been shown that the classical 24–48‐h component of delayed‐type hypersensitivity (DTH) in mice is preceded by an early 2‐h component. This early component of DTH resembles IgE‐dependent hypersensitivity reactions, but is mediated by an antigen‐specific T cell factor that activates cutaneous mast cells (MC). In the current study of cutaneous hypersensitivity reactions, evidence is presented that serotonin and histamine are released from the granules of MC in IgE‐dependent responses, but that T cell activation of MC induces preferential release of serotonin. In T cell‐dependent reactions, it was found that serotonin was released under experimental conditions in which MC granules were depleted of serotonin, but catabolism of serotonin in the cytosol was prevented. This suggests that T cells induce differential release of serotonin from nongranule storage sites in MC, such as transport vesicles in the cytoplasm. Morphological observations of MC in IgE‐dependent compared to T cell‐dependent cutaneous reactions were consistent with this hypothesis. Exocytosis of granules characterized IgE activation and was not found in MC that were activated by T cells, which instead showed mild degranulation accompanied by numerous cyto‐plasmic vesicles.
Pure interferon gamma enhances class II HLA antigens on human monocyte cell lines
Authors: Virelizier Jean‐Louis , Perez Nestor , Arenzana‐Seisdedos Fernando , Devos René
Published: February 2007

Human recombinant interferon gamma (IFN‐γ) with a chemical purity of over 90% was shown to enhance membrane expression of HLA‐DR antigens on cells from 3 human myelomonocytic lines (HL‐60, U‐937 and THP‐1). Immunofluorescence techniques using a series of anti‐HLA‐DR monoclonal antibodies showed that the low, although variable, levels of DR‐positive cells were clearly enhanced as soon as 24 h after incubation with IFN‐γ. Only IFN‐γ was able to exert this effect, since incubation with high concentrations of IFN‐α or ‐β did not induce any significant modification of the percentage of HLA‐DR‐positive cells. In contrast, doses of IFN‐γ as low as 2 units were effective, indicating a highly preferential, apparently selective effect of IFN‐γ for enhancement of HLA‐DR expression. Private class II antigen expression was also enhanced by IFN‐γ on the U‐937 cell line. Through its enhancing effect on class II public and private HLA antigens on the membrane of human monocytes, the IFN‐γ lymphokine may have a critical role in the modulation of antigen presentation by monocytes and on the regulation of HLA‐DR‐restricted cell cooperation.
Human B cell activation and cell cycle progression: stimulation with anti‐μ and Staphylococcus aureus Cowan strain I
Authors: Kehrl John H. , Muraguchi Atsushi , Fauci Anthony S.
Published: February 2007

The responses of resting human B lymphocytes to a variety of activation signals were studied. Human tonsillar B lymphocytes were separated according to size by countercurrent elutriation. The small B lymphocytes were then stimulated in vitro with various concentrations of anti‐μ antibody in the presence or absence of B cell growth factor (BCGF) or with Staphylococcus aureus Cowan strain I (SAC). Cellular volume changes and RNA synthesis were measured over the first 24 h of stimulation and were similar with either 15 μg/ml of anti‐μ, 100 μg/ml of anti‐μ, or SAC. In the subsequent 24 h, however, substantial increases occurred in the amount of RNA synthesis and cell enlargement only in those cultures stimulated with 100 μg/ml of anti‐μ or SAC, but not in the cultures stimulated with 15 μg/ml of anti‐μ. The addition of BCGF to those cultures stimulated with 15 μg/ml of anti‐μ did not alter the increases in cellular volume and RNA synthesis found 24 h after stimulation with anti‐μ alone. However, over the subsequent 24 h, the presence of BCGF in culture enhanced both B cell volume changes and RNA synthesis, when compared to cultures stimulated with 15 μg/ml of anti‐μ alone. In addition, BCGF enhanced DNA synthesis in cultures stimulated with low and high concentrations of anti‐μ. DNA content changes following stimulation with anti‐μ, anti‐μ plus BCGF, and SAC were also measured using propidium iodide staining and flow cytometry. Optimal concentrations of anti‐μ induced 20% of the resting B cells to enter S phase, while optimal concentrations of anti‐μ plus BCGF or SAC induced approximately 40%. Finally, prestimulation of resting B cells for 24 h with a low concentration of anti‐μ, sufficient for cell enlargement but not S phase progression, allowed for rapid entrance of the prestimulated B cells into S phase when a high concentration of anti‐μ or SAC was added. These findings suggest the existence of a control point in the progression of human B cells through the cell cycle. This control point is located in the G1 phase of the cycle and is reached 24 to 36 h after a surface immunoglobulin‐mediated stimulus.
Activation and proliferation signals in mouse B cells II. Evidence for activation (G0 to G1) signals differing in sensitivity to cyclosporine
Authors: Klaus Gerry G. B. , Hawrylowicz Catherine M.
Published: February 2007

We have previously shown that cyclosporine (CS) selectively inhibits polyclonal activation of B cells by anti‐Ig antibodies but not by lipopolysaccharide (LPS). Here we extend these results using a two‐stage B cell culture system in which cells from either CBA/N or normal mice are activated to enter G1 by anti‐Ig, and are then stimulated to proliferate by LPS. In this system CS blocks an event that occurs within 4 h after initial activation, i.e. prevents entry of B cells into G1. Phorbol myristic acetate also induces some CBA/N B cells to enter G1. However, activation of B cells by this agent is resistant to inhibition by CS. These data suggest that there are two biochemically distinct mechanisms for driving resting B cells into G1. A hypothesis to explain these results is presented.
T‐dependent activation of resting B cells mediated by concanavalin A
Authors: Ratcliffe Michael J. H. , Julius Michael H.
Published: February 2007

In cultures containing long‐term cultured lines of antigen‐specific helper T (Th) cells, normal unprimed B cells and concanavalin A (Con A), induction of B cells to immunoglobulin secretion and DNA synthesis was observed. The plaque‐forming cell (PFC) response was large (frequently > 75000 PFC/106 input B cells) demonstrating the polyspecific nature of the response. Con A‐mediated maturation and induction to DNA synthesis of responding B cells was completely Th cell dependent and inhibited with methyl‐α‐D‐mannoside. Both resting and blasted B cells, separated by Percoll density centrifugation were induced to DNA synthesis and immunoglobulin secretion. Responses were completely unrestricted by the B cell major histocompatibility complex, even at the level of the resting B cell. The polyclonal nature of the response taken together with the Con A‐mediated bypassing of T cell specificity and restricting haptotype indicates that this response is analogous to lectin‐mediated cytotoxicity.
A monoclonal antibody which differentiates between bound and free human secretory component
Authors: Gore Martin E. , Bunnage Hilary J. , McIlhinney Robert A. J.
Published: February 2007

In this study a mouse monoclonal antibody (LICR‐LON‐LC28) to human secretory component (SC) is reported. This antibody binds to free SC or to SC associated with IgA or IgM. It exhibits a 10‐fold higher affinity for SC bound to IgA than for free SC. The affinity of the antibody for SC associated with IgM is equivalent to that seen for free SC.

LICR‐LON‐LC28 appears to be species specific and does not cross‐react with other human milk proteins.
Clonal expression of differentiation and Ia‐like antigens on alloreactive human T lymphocytes
Authors: Schendel Dolores J. , Johnson Judith P. , Evans Robert L. , Wank Rudolf
Published: February 2007

A series of human T lymphocyte clones showing specific responses for major histocompatibility complex‐encoded alloantigens were isolated from a single culture. They were classified into distinct functional groups based on measurement of alloantigen‐specific proliferation and cytotoxicity. Surface antigen expression on these clones was analyzed using a panel of monoclonal antibodies specific for T cell differentiation antigens and for Ia‐like antigens. Four distinct groups were identified based on the Leu series of differentiation antigens: (a) Leu1+,2+,3+,4+; (b) Leu1+,3+,4+; (c) Leu1+,2+,4+; and (d) Leu2+,4+. Functionally distinct clones showed not only differential expression of Leu2 and Leu3, antigens which had previously been shown to distinguish helper/inducer and cytotoxic/suppressor cells, but also of Leu1, an antigen classified as a common T cell marker. All of the clones were found to express Ia antigens as detected by three framework monoclonal antibodies, but none were found to express a determinant associated with the DR3 allospecificity, although it was found on normal B lymphocytes and a B cell line established from the HLA‐DR3 individual from whom these clones were derived.
Frequency and activity of immune interferon (IFN‐γ)‐and colony‐stimulating factor‐producing human peripheral blood T lymphocytes
Authors: Kees Ursula , Kaltmann Brigitte , Marcucci Fabrizio , Hültner Lothar , Staber Fritz , Krammer Peter H.
Published: February 2007

This report describes the first frequency estimate of immune interferon (IFN‐γ)‐ and colony‐stimulating factor (CSF)‐producing human peripheral blood T lymphocytes. Human peripheral blood lymphocytes (HPBL) were activated with T cell mitogens [concanavalin A (Con A) or phytohemagglutinin (PHA)] in bulk culture and subsequently plated in limiting dilution (LD) microcultures in the presence of irradiated allogeneic HPBL filler cells and culture medium supplemented with human inter‐leukin 2 and T cell mitogen (Con A or PHA). HPBL growing in these cultures were T cells as determined by E‐rosetting (> 85%) and were positive for the OKT8 marker. The growth frequency (f) of HPBL in LD was f = 1/20‐1/100. Such cells were induced with T cell mitogens (Con A or PHA) to release lymphokines into the supernatant. Statistical analysis of the data from the LD experiments showed that (a) the precursor cell frequency for IFN‐γ‐ and CSF‐producing T cells was f = 1/63‐1/151 and 1/89‐1/217, respectively, and (b) most T cell clones released IFN‐γ and CSF simultaneously. In addition, individual T cell clones were shown to be capable of releasing different CSF types. In principle, this experimental system can be used to evaluate the precursor frequency, relationship and activity of normal or pathological human T cells performing any in vitro T cell function.
Antigenic polymorphism of Trypanosoma cruzi: clonal analysis of trypomastigote surface antigens
Authors: Plata Fernando , Pons Francisco Garcia , Eisen Harvey
Published: February 2007

The surface membrane antigens of infectious Trypanosoma cruzi trypomastigotes were studied at the levels of the strain and of individual trypomastigote clones. Blood trypomastigotes from three T. cruzi strains, Y, CL and Tehuantepec (“Teh”), were grown in vitro by weekly infection of J774 mouse macrophage tumor cells. Each T. cruzi strain was subsequently cloned by infection of J774 cells at limited trypomastigote dilution, and antisera were produced in mice against a selection of trypomastigote clones. Criss‐cross panel analyses indicated the existence of a large degree of polymorphism among trypomastigote surface antigens. Various trypomastigote surface antigens were cross‐reactive, appeared to be highly conserved, and were common to the three strains considered and to all the clones derived from each strain. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that numerous trypomastigote antigenic proteins were precipitated by mouse antisera generated against cloned trypomastigotes. Some of these proteins were commonly distributed, while others were polymorphic. Finally, a state of cross‐reactive immunity could be induced in C3H/He mice by infection with a cloned T. cruzi trypomastigote population. Immune mice resisted subsequent infections with lethal doses of wild‐type bloodstream trypomastigotes from any one of the three T. cruzi strains.
Heterogeneity of Igh‐linked allotypic determinants expressed on functional T cell subsets as detected by monoclonal antibodies
Authors: Karasuyama Hajime , Kim Musung , Okumura Ko , Tada Tomio
Published: February 2007

Hybridomas producing monoclonal antibodies (mAb) specific for immunoglobulin heavy chain (Igh) allotype‐linked gene products expressed only on functional T cells but not on B cells and macrophages were established by fusion of allotype congenic SJL (Igh‐1b) and SJA/9 (Igh‐1a) B cells immunized reciprocally with partner spleen cells with a myeloma P3‐X63‐Ag8‐653 of BALB/c origin. Nine mAb have been selected on the criteria that they can specifically block various antigen‐dependent functions of known T cell subsets in in vitro immune responses of mouse strains having the corresponding Igh allotype, but not the other one. These included (a) four mAb that augment the in vitro secondary antibody response of either Igh‐1a or Igh‐1b strains and thus are considered to react with the Igh‐linked allotypic determinant expressed on suppressor T cells, (b) one mAb that inhibits the helper T cell activity of Igh‐1b but not of Igh‐1a strains, (c) two mAb that inhibit the antigen‐induced pro‐liferative response of Igh‐1a but not Igh‐1b strains, and (d) two mAb that block the cytotoxicity of alloreactive cytotoxic T cells of Igh‐1a strains. The linkage to Igh‐1 allotype of the T cell products was established by testing with Igh‐1‐congenic strains with different backgrounds including the H‐2 complex. Some of the mAb were able to react with cloned hybridomas and a continuous cell line of the given allotype and functions. Each mAb was able to block one of the known functions of T cell subsets, but not others, indicating the existence of the heterogeneity and multiplicity of the Igh allotype‐linked products on T cells.
Interleukin 2‐independent stimulation of rabbit chondrocyte collagenase and prostaglandin E2 production by an interleukin 1‐like factor
Authors: Evěquoz Vlasta , Bettens Florence , Kristensen Flemming , Trechsel Ulrich , Stadler Beda M. , Dayer Jean‐Michel , de Weck Alain L. , Fleisch Herbert
Published: February 2007

In the present study, interleukin 1 (IL 1)‐containing media from different sources, namely a murine macrophage cell line (P388D1), rabbit peritoneal macrophages, and human peripheral blood mononuclear cells, were compared for their effect on thymocyte proliferation and on collagenase and PGE2 secretion by chondrocytes. A high correlation was found between the enhancement of thymocyte proliferation and the induction of collagenase and PGE2 secretion by chondrocytes. Furthermore, a highly purified IL 1‐like factor, namely mononuclear cell factor (MCF) was also active on chondrocytes. The addition of highly purified IL 2 to rabbit chondrocytes had no effect on collagenase and PGE2 secretion induced by IL 1‐containing media. Our findings suggest that the factor which induced collagenase and PGE2 secretion by rabbit chondrocytes was an IL 1‐like factor. Thus, collagenase secretion by chondrocytes may be used as an IL 2‐insensitive assay for the detection of IL 1‐like factors.
Activation of human T lymphocytes II. Involvement of the T3 antigen in polyclonal T cell activation by mitogenic lectins and oxidation
Authors: Fleischer Bernhard
Published: February 2007

The effect of monoclonal antibodies against the T cell surface antigens T3 and T4 on accessory cell‐dependent mitogen‐induced proliferation of human antigen‐specific T4+ T lymphocyte clones and purified peripheral blood T cells was studied. To avoid the Fc receptor‐dependent mitogenic effects of the OKT3 antibodies, monocytes were replaced by Epstein‐Barr virus‐transformed B lymphoblastoid cells as accessory cells. Monoclonal antibody OKT3 but not OKT4 inhibited the response of both T lymphocyte clones and purified T cells to mitogenic lectins and oxidation. The inhibition was not due to nonspecific effects of the monoclonal antibodies since it affected only the initial triggering but not the proliferation of activated T cells and it could be overcome by higher concentrations of lectin indicating a competition between OKT3 antibody and lectin. Furthermore, OKT3 antibody at the same concentration that was inhibitory in this system was mitogenic in the presence of Fc receptor‐bearing monocytes. Surface modulation of T3 but not of T4 antigens led to unresponsiveness to a mitogen pulse given directly after modulation. These findings suggest that antigen‐specific and mitogen‐induced T cell triggering are due to interaction with the same receptors of the T lymphocyte.
The “natural resistance” to bone marrow allografts in normal and athymic nude rats Rapid cytotoxic reactions both in vivo and in vitro
Authors: Rolstad Bent , Benestad Haakon B.
Published: February 2007

To elucidate the rapid destruction of allogeneic bone marrow (BM) grafts in nonsensitized rats we have assessed: (a) the 21‐h tissue localization of 51Cr‐labeled allogeneic vs. syngeneic BM cells, (b) the ability of allogeneic BM cells to proliferate in the BM of irradiated recipients, (c) the survival of allogeneic vs. syngeneic BM cells in cell‐impermeable diffusion chambers implanted into the peritoneal cavity of rats, and (d) the destruction of allogeneic vs. syngeneic labeled BM cells in vitro by effector cells from various lympho‐myeloid tissues.

Some allogeneic BM cells were destroyed within 24 h after transfer to athymic nude rats, thus demonstrating the thymus independence of the cytotoxicity. Furthermore, allogeneic BM cells also failed to proliferate in the BM of irradiated recipients. However, the survival of allogeneic BM cells was not impaired if they were sheltered from host cells within cell‐impermeable diffusion chambers over a culture period of 4 days. But when the allogeneic BM cells were similarly cultured in hosts presensitized against the BM donor, a substantial reduction in BM cell survival was observed. The effector cells of allogeneic BM cytotoxicity (ABC) were present in the spleen because PVG‐rnu spleen cells were highly effective in lyzing BM cells from the AO, but not the PVG strain in vitro after only 4 h of culture. Some ABC activity in vitro was also found for peripheral blood lymphocytes and lymph node cells, but not for BM cells themselves. Taken as a whole these data provide firm evidence that the “natural resistance” to BM allografts is basically different from conventional immune responses, and in most, but not all respects resembles natural killer activity.
The origin of follicular dendritic cells in the mouse and the mechanism of trapping of immune complexes on them
Authors: Humphrey John H. , Grennan Deirdre , Sundaram Vijaya
Published: February 2007

F1 → parental bone marrow chimeras between CBA and B10 mice were used to show that even after 1 year follicular dendritic cells (FDC), also termed dendritic reticular cells, are not derived from bone marrow stem cells. However clusters of cells wrapped in the dendritic processes of FDC, isolated by enzyme digestion of the spleen contain B cells originating from donor marrow. This implies that evidence for the presence of antigens such as Ia‐like detected by others (Gerdes, J. and Stein, H., Clin. Exp. Immunol. 1982. 48: 348) by immunohistology in or on FDC clusters should be interpreted with caution.

Deposition of immune complexes on mouse spleen FDC depends upon the presence of a radio‐ and cyclophosphamide‐sensitive population of cells, although FDC themselves are resistant to such treatments. After whole body irradiation the capacity to localize fluorescein isothiocyanate‐labeled aggregated human gamma globulin can be restored by normal or T‐deprived spleen cells, but restoration requires an interval of more than 1 though less than 5 days. These findings are compatible with the evidence of Gray et al., Eur. J. Immunol. 1984. 14: 47, that in the rat immune complexes are transported to FDC by a sessile population of marginal zone lymphocytes, as first suggested by Brown et al., Immunology 1973. 24: 955.
Degradation of specificity in cytolytic T lymphocyte clones: Mouse strain dependence and interstrain transfer of nonspecific cytolysis
Authors: Wilson Anne , Shortman Ken
Published: February 2007

Limiting‐dilution culture of murine Ly‐2 T cells with concanavalin A (Con A) and irradiated spleen filler cells produces, with high efficiency, cytolytic T lymphocyte (CTL) clones. With most mouse strains (including CBA and C57BL/6) the specificity of these CTL clones drops after day 6 of culture, so that by day 9 the majority of clones can lyse most murine target cells, whether syngeneic or allogeneic. The rate of specificity degradation and relative target cell preference varies with the mouse strain. Some strains (e.g. BALB/c) do not show this effect and CTL clones remain specific to day 9. Many low natural killer (NK) cell strains (e.g. C57BL/6J.bg) maintain CTL specificity in such cultures, but the correlation between CTL specificity and NK status is not absolute. Growth of BALB/c precursor cells on CBA filler cells leads to specificity degradation in the BALB/c CTL clones; however, the specificity of CBA‐derived CTL clones is not maintained by growth on BALB/c fillers. The results suggest that specificity degradation is induced in the developing CTL‐clone by factors in the culture environment, perhaps a soluble lymphokine (a differentiation factor) or by an infectious agent (an endogenous mouse virus). Although such CTL specificity loss may render many limiting dilution studies of the CTL specificity repertoire invalid, the problem may be bypassed by an appropriate choice of mouse strain.
Distinct epitopes are recognized by cytolytic T lymphocyte clones on the same class I molecule: direct demonstration using DNA‐transfected targets and longterm cytolytic T cell clones
Authors: McLaughlin‐Taylor Elizabeth , Woodward Jerold G. , McMillan Minnie , Frelinger Jeffrey A.
Published: February 2007

By producing long‐term, stable, cytolytic T lymphocyte clones and utilizing targets expressing only a single gene product derived from the stimulator mouse strain, we have been able to directly demonstrate that T cells recognize distinct epitopes expressed on a single H‐2 molecule. These multiple determinants are distinguishable by inhibition patterns with monoclonal antibodies (mAb). When two T cell clones, P‐2.14 and P‐2.17, are tested on an L cell transfected with the Dp gene (λ12a), the T cells kill the transfected targets as well as blasts derived from Dp mouse strains. mAb 7‐16.10 inhibits recognition and killing of Dp targets by both P‐2.14 and P‐2.17. This mAb 7‐16.10, however, competees with H‐2.m22. Interestingly mAb 11‐20.3 which also recognizes the H‐2.m22 specificity inhibits clone P‐2.14 but not P‐2.17. The mAb 7‐16.10, however, competes with 11‐20.3 for binding to the surface of L cells expressing the Dp gene. Thus the two T cells must recognize an overlapping specificity. Other mAb which bind to the H‐2Dp molecule are unable to inhibit either of these two cytolytic T cell clones. Paradoxically, any of the mAb when tested individually are sufficient to inhibit the polyclonal response derived from in vitro mixed lymphocyte culture.

Therefore, by using targets expressing only a single H‐2 molecule derived by DNA‐mediated gene transfer and cytolytic T cell clones we have been able to directly demonstrate the presence of multiple epitopes on a single molecule and define their inhibition with mAb directed to that same molecule.
Characterization of stromal cell populations in the developing thymus of normal and nude mice
Authors: Kingston Rosetta , Jenkinson Eric J. , Owen John J. T.
Published: February 2007

The role of the thymic stromal components in T cell maturation has been investigated by compairing stromal composition in the developing thymus of normal mice with that of nude mice which are unable to support thymopoiesis. Stromal cell populations have been characterized using monoclonal antibody recognizing class II (Ia) major histocompatibility complex antigens, monoclonal antibody A2B5 recognizing GQ gangliosides characteristic of neuroendocrine cells and monoclonal antibody LE.61 recognizing a determinant associated with the tonofilaments of simple epithelia.

Using these probes we have shown that the majority population of Ia+, LE.61+ cells is distinct from the A2B5+ stromal population and that both these populations appear early in normal thymus development showing a similar pattern in vivo and in thymus lobes developing in organ culture. In the nude thymic rudiment both Ia and LE.61 labeling are absent supporting previous conclusions on the epithelial nature of the thymic defect in these animals. In contrast, A2B5+ cells are present in the nude thymic rudiment indicating that these cells are unlikely to share the same developmental origin as the Ia+ epithelial population.

In functional terms these results suggest that the Ia+ LE.61+ components, deficient in the nude mouse, are essential for normal thymus function and that whatever the function of the A2B5+ population, alone they are not sufficient to support thymocyte development.
Cytotoxic T cell responses to haptenated cells IV. Requirements for in vivo priming
Authors: Haas Werner , Mathur‐Rochat Jacqueline , Pohlit Helmut , Boehmer Harald Von
Published: February 2007

Hapten‐specific cytotoxic T cells (CTL) can be generated in cultures containing mouse spleen cells and hapten‐coupled syngeneic stimulator cells. A response to sparsely hapten‐coupled stimulator cells is only obtained with responder cells from immunized H‐2k mice. Immunization was effective with hapten coupled to syngeneic, allogeneic or xenogeneic nucleated cells or membranes thereof. Hapten‐coupled erythrocytes, bacteriophages or soluble proteins did not induce CTL precursors (CTL‐P) nor responses of other lymphocytes which would interfere with the response of CTL‐P. The results show that antigen presentation to CTL‐P is very efficient in vivo. Haptens could be presented to and recognized by CTL‐P only if coupled to surface membranes of nucleated cells.
HLA‐DR‐, MB‐ and novel DC‐related determinants restrict purified protein derivative of tuberculin (PPD)‐ stimulated human T cell proliferation
Authors: Pawelec Graham , Schneider E. Marion , Miiller Claudia , Wernet Peter
Published: February 2007

Class II major histocompatibility complex determinants restricting recognition of tuberculin antigens (purified protein derivative; PPD) were studied by using mono‐ clonal antibodies (mAb) to block lymphoproliferative responses. Anti‐class I1 mAb were shown to exert inhibitory effects at the level of the antigen‐presenting cells, without inducing suppressive lymphocytes or macrophages. Using panels of HLA‐ typed antigen‐presenting cells and nonalloreactive proliferative T cell lines, derived by limiting dilution, restriction elements for PPD responses appeared to correlate with the donor's HLA‐DRw6 specificity (one clone), MB1 (one clone), MB3 (one clone), or no established class II (or class I) specificity (three clones). mAb TÜ22, reacting with nonpolymorphic DC‐like determinants, strongly inhibited stimulation of all clones except that restricted by DR antigens, suggesting the DC‐like character not only of the MB1‐ and MB3‐associated, but also of the unassigned, restriction elements of these cloned lines. In contrast, stimulation of the DR‐restricted line was strongly inhibited by DWSB‐specific mAb which only weakly inhibited the stimulation of clones restricted by DC‐like determinants. These results suggest that clonally distributed PPD‐reactive proliferative lymphocytes from a single donor may be restricted by at least three different class Il determinants (HLA‐DR, MB, or a second, novel, DC‐related molecule).
Regulation of thymocyte proliferative response by macrophage‐derived prostaglandin E2 and inter leukin 1
Authors: Hayari Yacov , Kukulansky Tova , Gloherson Amiela
Published: February 2007

The antagonistic effects of macrophage (MΦ)‐derived interleukin 1 (IL1) and prostaglandin Ez (PGE2) on thymocyte proliferation were uncoupled and studied. Elimination of PGE2 from the culture medium of prostaglandin Ez‐stimulated MΦ was achieved by dialysis of the media or by indomethacin treatment of the Ma. IL1 secretion appears to be PGE2 independent. Experiments using exogenous PGEzrevealed a quantitative relationship between the two monokines. PGE2 (1.25 ng/ml) reduced the proliferative effect of IL 1 produced by 1.5 × 105 peritoneal MQ, to 50%. This PGE2 dose increased significantly the levels of intracellular cAMP. Separation of peritoneal exudate MΦ on a bovine serum albumin discontinuous gradient demonstrated that the main part of PGE2 synthesis was in a fraction of lower density, large MΦ, whereas IL1 activity was detected in all tested fractions.
Enhancement of human B cell proliferation by an antibody to the C3d receptor, the gp 140 molecule
Authors: Frade Raymond , Crevon Marie Claude , Barel Monique , Vazquez Aimè , Krikorian Laure , Charriaut Christiane , Galanaud Pierre
Published: February 2007

The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor activity is carried by a gp140 membrane antigen. A polyclonal antibody has been prepared by immunizing a rabbit with highly purified gp140 molecule isolated from membranes of the human B lymphoblastoid cell line Raji and its high specificity was previously demonstrated. We tested the effect of this antibody to the C3d receptor on the B cell proliferative response. Purified B cells from human blood were induced to proliferate by a B cell growth factor (BCGF)‐containing partially purified supernatant from activated T cells. The anti‐C3d receptor F(ab′)2 enhanced the BCGF‐dependent B cell proliferation. This effect was dose dependent, was observed in the presence of different concentrations of BCGF and did not correspond to a change in the time course of the response. The anti‐C3d receptor F(ab′)2 had no mitogenic effect in the absence of T cell supernatant. In contrast the undigested anti‐C3d receptor IgG suppressed the BCGF‐dependent B cell proliferation. These results emphasize the potentialities of anti‐gpl40 F(ab′)2 to explore the involvement of the C3d receptor in the regulation of B cell response to T cell products.
Genetically determined molecular weight differences in murine complement component C6
Authors: Orren Ann , Preece Celia J. , Dowdle Eugene B.
Published: February 2007

Plasma samples from male CBA, BALB/c and DBA/2 mice were subjected to poly‐acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Bands of C6 hemolytic activity in the washed resolving gel were identified by means of an erythro‐cyte/agarose overlay gel. CBA plasma was found to contain two forms of C6, one with a molecular weight (M,) of approximately 90 000 (type A) and one with a M, of 100000 (type B); CBA mice were thus designated C6 : A+B+. BALBk and DBAR plasma on the other hand contained only the low molecular weight type A C6 and were designated C6: A+B−. Flat bed isoelectric focusing followed by functional overlays showed that CBA plasma produced two sets of hemolytic bands (PI 5.25–5.4 and 5.0–5.2) whereas BALB/c and DBA/2 plasma produced only the more cathodal band set. The additional band set in CBA plasma corresponded to the high‐Mr type B C6. Results of breeding experiments demonstrated that the possession of the high Mrtype B C6 was inherited in the manner of an autosomal phenotypically dominant characteristic.
Immunologic memory to phosphorylcholine. VI. Heterogeneity in light chain gene expression
Authors: Todd Ian , Brown McKay , Rittenberg Marvin B.
Published: February 2007

BALB/c mice immunized with phosphorylcholine‐conjugated keyhole limpet hemocy‐anin (PC‐KLH) produce two types of anti‐PC antibodies, designated group I and group II, which differ in their fine specificity and idiotype expression. Group I1 hybridomas can utilize VH genes and VL genes (in particular, Vϰ1–3) distinct from those expressed in the group I‐like anti‐PC myelomas. Here we have analyzed additional anti‐PC hybridomas from BALB/c and (CBA/N × BALB/c)F1 male mice and also anti‐PC antibodies purified from BALB/c and C57BL/6N antisera. Isoelectric focusing indicates that one of the group II hybridomas utilizes Vϰ1–3 and that related L chains are expressed in a major portion of group II serum antibodies. Other group I1 antibodies in antisera express different L chains, some of which are presently unidentified. However, isoelectric focusing analysis also indicates that the L chains of some group I1 hybridomas and serum antibodies are related to those found in the group I anti‐PC myelomas and group I hybridoma and serum antibodies. In addition, one hybridoma was found to utilize λ2. Thus, it appears that the anti‐PC antibodies with group II‐like fine specificity can utilize a variety of VL genes related to, or distinct from, those expressed in group I antibodies.
Cyclosporin A inhibits antigen‐ and lectin‐induced but not constitutive production of interleukin 3
Authors: Palacios Ronald
Published: February 2007

Cyclosporin A (CyA) strongly inhibited production of interleukin 3 (IL 3) by normal mouse spleen cells and by the T lymphoma LBRM‐33 clone 1A5 induced by alloanti‐gens and by the lectins concanavalin A or phytohemagglutinin. At the same concentrations at which CyA exerted this suppressor activity, it did not affect the growth of the Ea3.15 pre‐B cell clone supported by recombinant mouse IL3 (the read‐out for IL3 activity used in this study) nor did it show significant inhibitory effect on the spontaneous secretion of IL3 by WEHI‐3 cells and by the LD1 T helper line. Taken together, these observations indicate that CyA does not interfere with translation, synthesis or secretion of IL3. CyA most likely interferes with the process by which antigens and lectins induce transcription of genes coding for lymphokines.
Tissue distribution and ontogenic appearance of a chicken T lymphocyte differentiation marker
Authors: Houssaint Elisabeth , Diez Elisabeth , Jotereau Francine V.
Published: February 2007

A monoclonal antibody, designated T10A6, was produced by immunizing mice with H. Bl4 chicken thymocytes. T10A6, when tested by immunofluorescence, labeled 80% of thymocytes, and a subset of peripheral T cells: 20% of spleen leukocytes, 10% of blood leukocytes, 8% of bone marrow cells but less than 1% of bursal lymphocytes. Tissue distribution on polyethylene glycol sections showed that in the thymus T10A6 stained most cortical thymocytes and a portion of medullary cells. In the spleen, the positive cells appeared scattered mainly in the T‐dependent areas. Ontogenic studies revealed that the antigen recognized was found in the chick embryo thymus from day 11 onward and the expression of this antigen on thymocytes reached the adult level from day 13. The first positive cells were detected in the spleen on day 13 of embryonic life. T10A6 (IgG1) precipitated a 65‐kDa material from thymocytes. This is the first description of a monoclonal antibody recognizing a peripheral T cell subpopula‐ tion in chicken.
Recombinant interleukin 2 differentiates alloantigen‐primed Lyt‐2+ T cells into the activated cytotoxic state
Authors: Yoshimoto Ryota , Kashima Nobukazu , Okada Kyoko , Amikura Keiko , Hamuro Junji
Published: February 2007

The possibility of the generation of secondary cytotoxic T lymphocyte (2oCTL) activity from alloantigen primed T cells by genetically homogeneous recombinant human interleukin 2 (G‐IL2) was analyzed. Not only purified IL2 by cell culture (C‐IL2) but also G‐IL2 induced 2oCTL activity from primed T cells generated in mixed lymphocyte culture. This induction process required RNA and protein synthesis, while DNA synthesis was not relevant. In parallel to the induction of 2oCTL activity, transition of the primed cells from the resting G1a to activated G1b has taken place. 2oCTL activity was induced from nylon column‐purified primed T cells in the absence of accessory cells and also in the absence of Lyt‐1+ T cells. Interferon‐y (IFN‐γ) induction was detected during the course of activation of alloantigen‐primed T cells into the cytotoxic state. When IL2 was absorbed, IFNγ in the culture supernatant did not induce 2oCTL activity. These results suggest that the IL2 molecule possessing T cell growth factor properties shares the nature of differentiation factor in terms of the activation of alloantigen‐primed T cells into cytotoxic state. The role of IFN‐γ produced in situ for this activation process awaits further investigation.
Enumeration of lymphocyte‐target cell conjugates by cytofluorometry
Authors: Berke Gideon
Published: February 2007

Using fluorescein‐labeled effector lymphocytes and tetramethyl rhodamine‐labeled target cells a cytofluorometric method is described for the detection and quantification of lymphocyte‐target cell cluster (conjugate) formation. Conjugation levels mea‐ sured by cytofluorography correspond well with those scored microscopically. The method has so far been used successfully to monitor conjugate formation by specifically sensitized cytotoxic T lymphocytes (CTL). In preliminary experiments it has been applied to nonspecific, lectin concanavalin A‐dependent conjugate formation by CTL, as well as to conjugates formed by hybridoma CTL. The procedure has potential application in other cell‐cell interactions, relevant to immunology as well as to cell biology.
Antigen processing by macrophages: definition of the ligand recognized by T‐inducer cells
Authors: Puri Joseph , Abromson‐Leeman Sara , Cantor Harvey
Published: February 2007

An interaction between antigen and macrophage‐like cells which display I region gene products [antigen‐presenting cells (APC)] is necessary for activation of inducer T cell clones. The specificity of inducer cell activation has been found to be major histocom‐ patibility complex (MHC)‐restricted and antigen specific. This is thought to reflect formation of a ligand consisting of MHC class II gene products associated in some way with foreign protein.

A panel of inducer T cell clones with different activation specificities and homogene‐ ous lines of APC expressing different MHC haplotypes was used to define this ligand. We isolated a product formed after interaction between antigen and APC expressing defined MHC products. This ligand binds only to the T cell clones that are specifically activated by the same antigen and APC as judged by tritiated thymidine incorpora‐ tion. The ligand is composed of two moieties: I‐A determinants and the foreign protein (“antigen”). Coelution and sequential precipitation studies of the two moieties indicate that the nominal antigen and MHC product are tightly linked. The implications of these findings are discussed.
Activation of Lyt‐2+ T cells by antibodies towards brain‐associated antigens. I. Accessory cell requirement and role of Fc receptors in the induction of reactivity to interleukin 2
Authors: Gullberg Martin , Carlsson Sven R. , Larsson Eva‐Lotta
Published: February 2007

The present report describes a system where essentially all Lyt‐2+ T cells are selectively activated by rabbit anti‐mouse brain antibodies (RaMB) to interleukin 2 (IL 2) reactivity. High efficiency of RaMB‐mediated induction was obtained by a 5 h incubation with antibodies at high cell density of Sephadex G‐10‐nonadherent spleen cells. No in situ production of IL 2 by RaMB‐treated cells was detected, and proliferalive responses were entirely dependent on exogeneous IL2. RaMB‐induced IL2 reactivity was found to require accessory cells which are Fc receptor positive, and clearly distinct from those required to induce T cell proliferation in mixed lymphocyte cultures. We conclude that Lyt‐2+ T cells are triggered to IL2 reactivity by Fc receptor ‐ mediated presentation of RaMB antibodies. The mechanism of induction by RaMB antibodies is discussed. This work was supported by the Swedish Medical Research Council, Stiftelsen Jubileumskliniken (Lions project 254/82) Umea, Sweden, and a grant from the Ministry of Research and Technology, France.
Signal requirements for the in vitro differentiation of cytotoxic T lymphocytes (CTL): distinct soluble mediators promote preactivation of CTL‐precursors, clonal growth and differentiation into cytotoxic effector cells
Authors: Hardt Conny , Diamantstein Tibor , Wagner Hermann
Published: February 2007

We describe here that the requirement of accessory cells for the polyclonal activation of high‐density (resting) murine T lymphocytes can be bypassed by soluble mediators present in culture supernatants of concanavalin A (Con A)‐activated murine spleen cells. Induction of responsiveness is confined to Lyt‐2+ T cells; GK 1.5+ T helper cells require signals provided by accessory cells. Using this system the lymphokine signal requirements for the polyclonal activation of Lyt‐2+ cytotoxic T lymphocyte (CTL) precursors could be defined. We show that Con A fails to trigger in Lyt‐2+ responder T cells the expression of interleukin 2 (IL 2) receptors and assume that this explains why recombinant (rec) DNA‐derived IL2 fails to induce proliferative responses. Complementation of rec IL2 with an IL2 receptor‐inducing factor (RIF) induces proliferative responses. RIF alone triggers IL2 receptor expression in 10–12% of Lyt‐2+ T cells exposed to Con A. This lymphokine appears to be distinct from colony‐stimulating factor 1, IFN‐γ and IL1.

Resting Lyt‐2+ T cells cultured in limiting numbers in the presence of Con A, RIF plus rec IL2 do proliferate, yet exhibit no cytolytic activity. Differentiation into CTL can be brought about by addition of cytotoxic T cell differentiation factor (CTDF). We conclude that the polyclonal activation pathway of CTL from resting CTL precursors can be subdivided into three stages: preactivation, clonal growth and CTL differentiation. Each of these stages appears to be controlled by a distinct lymphokine, RIF, IL2 and CTDF, respectively.
Helper T cell requirements for T15 idiotype expression on phosphorylcholine‐specific antibodies
Authors: Hathcock Karen S. , Kenny James J. , Hodes Richard J.
Published: February 2007

The requirement for idiotype‐specific T Cells was investigated in the T15 idiotype‐ dominant T cell‐dependent response of unprimed BALB/c and (BALB/c × C57BL/6)F1 B cells to phosphorylcholine (PC). It was first demonstrated that cloned keyhole limpet hemocyanin (KLH)‐specific, major histocompatibility complex (MHC)‐restricted T helper (Th) cells as well as heterogeneous KLH‐primed Th populations were capable of generating PC‐specific antibody responses in T‐depleted unprimed B cell populations cultured in the presence of PC‐KLH. The PC‐binding antibody responses generated under these conditions were indistinguishable when assayed for carrier‐hapten linkage requirements, immunoglobulin isotype (predominantly IgM) or PC affinity. Further, it was observed that the PC‐binding antibodies which were generated in the presence of these two T cell populations expressed equivalently high levels of T15 idiotype. Assaying antibody and idiotype by either enzyme‐linked immunosorbent assay or plaque‐forming cell assay yielded similar results. Since monoclonal MHC‐restricted, KLH‐specific Th cells presumably lack any additional T cell populations, these results argue against an absolute requirement for anti‐idiotypic Th cells in the generation of T15‐dominant antibody responses.
Secretion of IgG1 induction factor by T cell clones and hybridomas
Authors: Sideras Paschalis , Bergstedt‐Lindqvist Susanne , MacDonald H. Robson , Severinson Eva
Published: February 2007

IgG1 induction factor elevates the IgGl response induced by lipopolysaccharide and suppresses the lipopolysaccharide‐induced IgG3 and IgGZb responses in cultures of mouse spleen cells. We have developed new T cell lines secreting this factor by cloning mixed lymphocyte culture populations. Using supernatants of one of these T cell lines it was found that the assay is quantitative, reproducible and accurate, both when induction of IgGl as well as reduction of IgG3 and IgG2b were measured. Using this analysis, different conditions to induce maximal production of the factor were tested. The cell line was thereafter used as fusion partner with a T cell lymphoma. The hybrids were selected in the presence of T cell growth factor and all of them secreted IgGl induction factor.