bluuebunny/crossref_metadata_2025 huggingface dataset:
Cells of the marginal zone of the spleen are lymphocytes derived from recirculating precursors
Authors: Kumararatne Dinakantha S. , MacLennan Ian C. M.
Published: February 2007

The origin of the B cells of splenic marginal zones was studied using transfer experiments in rats depleted of marginal‐zone cells. Cyclophosphamide given as a single dose of 500 mg/m2 was used to deplete the marginal zones. Approximately 90% depletion was still apparent 10 days after treatment. Fetal liver cells did not induce rapid repopulation of the marginal zone. Also bone marrow cells from rats depleted of recirculating lymphocytes were inefficient in this respect. Conversely, thoracic duct lymphocytes and bone marrow cells from normal rats were efficient at restoring marginal‐zone cell numbers in cyclophosphamide‐treated rats. Thoracic duct cells passaged through an irradiated intermediate host and collected from that host's thoracic duct were also efficient at achieving marginal‐zone cell reconstitution. In rats receiving 1000 rd whole body irradiation, which were protected with fetal liver cell transfer, marginal zones did repopulate at about 3 weeks. It is concluded that marginal‐zone B cells, after leaving primary lymphoid organs, enter the recirculating pool for a period of at least several days before settling in the marginal zone. The turnover rate of marginal‐zone cells was assessed using tritiated thymidine infusion. Most marginal‐zone cells were not labeled after 5 days continuous labeling suggesting that the marginal‐zone B cells are not rapidly dividing.
Enhancement of Fcγ receptor expression in interferontreated mice
Authors: Aguet Michel , Vignaux Françoise , Fridman Wolf H. , Gresser Ion
Published: February 2007

Treatment of C3H mice with partially purified or highly purified virus‐induced interferon resulted in a marked increase in the expression of Fcγ receptors (FcγR) on splenic lymphocytes, mesenteric lymph node cells and thymocytes from cortisonetreated mice. An increase in FcγR on splenic lymphocytes was seen as early as 5 h and lasted at least 72 h after a single injection of interferon. We suggest that enhancement of FcγR is one of the mechanisms by which interferon exerts some immunostimulating effects in vivo.
Characteristics of a poly(LTyr,LGlu)‐poly(DLAla)–poly(LLys)‐specific helper factor derived from a T cell hybridoma
Authors: Apte Ron N. , Eshhar Zelig , Löwy Ilana , Zinger Heidy , Mozes Edna
Published: February 2007

A poly(LTyr,LGlu)‐poly(DLAla)‐poly(LLys) [(T,G)‐A‐L]‐specific helper T cell hybridoma, R‐9, was established by fusing activated T cells, enriched for specific helper activity by incubation on antigen‐pulsed splenic adherent cells, with the BW5147 thymoma line. Supernatants of this hybrid line or its active clones as well as ascitic fluids, aspirated from the peritoneum of mice injected with the hybridoma cells, manifest a(T,G)‐A‐L‐specific helper T cell‐replacing activity as assayed in an in vitro hapten‐carrier antibody production system. The factor activity can be specifically absorbed on and eluted from columns of immobilized (T,G)‐A–L, antibodies directed against the variable region of the immunoglobulin heavy chain and an antiserum directed against (T,G)‐A‐L‐specific idiotypes. Although the R‐9 factor and anti‐(T,G)‐A‐L antibodies share V region gene‐encoded determinants, they differ in their fine antigenic specificity, as determined by cross‐reactivity with closely related synthetic polypeptide immunogens. Whereas anti‐(T,G)‐A–L antibodies bind equally well to the L‐phenylalanine‐ or L‐histidine‐containing polypeptides (Phe,G)‐A‐L and (H,G)‐A‐L, to poly(LGlu)‐poly(DLAla)‐poly(LLys) (G‐A–L) and poly(Tyr,Glu)‐poly(LPro)‐poly(LLys) [(T,G)‐Pro–L], the R‐9 factor was completely absorbed on columns of (Phe,G)‐A‐L and G‐A‐L and only partially absorbed on immobilized (T,G)‐Pro–L and (H,G)‐A‐L. In addition to V region gene products, the R‐9 factor also bears major histocompatibility complex (MHC) determinants, which were found to map to the left end of the Ib region. Combination of inactive effluents obtained after absorption of the R‐9 factor on columns of anti‐H‐2b and anti‐Id antibodies resulted in active factor preparations, suggesting that although V region gene and MHC products are linked together in the active part of the factor, these moieties are located on different polypeptide chains which may associate in solution.
Characterization of murine newborn inhibitory T lymphocytes: functional and phenotypic comparison with an adult T cell subset activated in vitro by alphafetoprotein
Authors: Murgita Robert A. , Hooper D. Craig , Stegagno Michele , Delovitch Terry L. , Wigzell Hans
Published: February 2007

Inhibitory T lymphocytes isolated from the spleens of newborn CBA/J mice which have high intrinsic levels of alpha‐fetoprotein (AFP) were compared, in terms of surface antigen phenotype and mode of immunosuppressive action, with a population of adult spleen T cells activated in vitro by a 4‐day preculture in the presence of purified AFP. The suppressing ability of these two groups of T cells was assayed on in vitro antibody synthesis of adult spleen cells to the T‐dependent (TD) and T independent (TI) antigens, sheep red blood cells and 2,4‐dinitrophenylated Ficoll. Negative selection of T cell subpopulations with antisera and complement showed that the inhibitory activity of newborn and adult AFP‐activated T cells on anti‐sheep red blood cell responses was abrogated by anti‐Thy‐1 anti‐Lyt 1, and by anti‐Iak (A. TH anti‐A. TL), whereas anti‐Lyt 2 antiserum and complement had no effect. Cytotoxic pretreatment with a panel of alloantisera specific for distinct products of major histocompatibility complex I subregions indicated that the Ia antigens expressed on the inhibitory T cells included I‐J, but not I‐EC determinants. Newborn and adult AFP‐activated inhibitory T cells could thus be shown to belong to a very similar, if not identical, subset of T lymphocytes characterized by the Thy‐1+, Lyt‐1+2−, I‐J+ phenotype. Both groups of T lymphocytes were shown to behave like efficient suppressor inducer cells in that they augmented TD antibody responses when added to purified B cell cultures which could not respond to TD antigen on their own, but caused strong inhibition of these responses when normal T cells were present. Dilution analyses of the two groups of inhibitory T cells showed that efficient suppressive activity was highly selective for TD responses, compared with a relatively weak inhibitory effect on TI responses. Passive administration of anti‐I‐J alloantibodies into newborn animals resulted in a significantly increased ability to respond to TD antigen, suggesting an anti‐I‐J‐mediated disruptive effect on newborn suppressor mechanisms. Our findings, therefore, indicate that TD antibody responses in newborn mice are regulated by an I‐J+ T cell‐mediated feedback inhibition circuit. Based on functional and phenotypic analyses, our results further suggest the probable identity of the naturally occurring inhibitory T cells in newborn mice and a subset of adult spleen T cells activated in vitro by AFP. This supports the contention that AFP may function as an important immunoregulatory agent in vivo.
Defective antigen presentation by macrophages from mice genetically selected for low antibody response
Authors: Adorini Luciano , Doria Gino
Published: February 2007

Mice, selected for high (H) and low (L) antibody responses to xenogeneic erythro‐cytes (Biozzi mice, selection I), have been tested for their immune responsiveness to lysozymes. The anti‐ring‐necked pheasant egg‐white lysozyme (REL) and anti‐hen egg‐white lysozyme (HEL) primary plaque‐forming cell responses are 20 to 40‐fold lower in L than in H mice. The heterogeneity of anti‐HEL antibodies in the secondary response, as analyzed by isoelectric focusing, is highly reduced in L as compared to H mice. The in vitro anti‐HEL plaque‐forming cell secondary response of (H × L)F1 lymph node (LN) cells is induced by HEL‐pulsed macrophages (Mϕ) from H, but not from L, mice. Therefore, genetic differences affecting antibody responsiveness in H and L mice are expressed at the level of antigen‐presenting cells. This genetic defect observed in L cells has been studied in more detail using an antigen‐specific, T cell‐dependent LN cell proliferative assay. After HEL‐complete Freund's adjuvant (CFA) priming, LN cells from H or (H × L)F1 mice respond to HEL, REL (which is cross‐reactive with HEL) and purified protein derivative of tuberculin (PPD), whereas LN cells from L mice do not respond to HEL or REL but proliferate in the presence of PPD. Proliferation of HEL‐CFA primed (H × L)F1 LN cells is induced by HEL‐ or REL‐pulsed Mϕ from H but not from L mice, whereas PPD‐pulsed Mϕ from H or L mice give similar proliferative responses. By increasing 50‐fold the concentration of HEL used to pulse Mϕ from H and L mice, a comparable proliferative response is obtained when HEL‐CFA‐primed (H × L)F1 LN cells are stimulated with HEL‐pulsed Mϕ from either line. This finding indicates that the genetic defect at the antigen‐presenting cell level in L mice is not absolute, but rather reflects a different antigen handling by Mϕ in the two lines.
Lympho‐stromal interactions in the thymus: medullary thymocytes react with I‐A determinants on autochthonous thymic stimulator cells
Authors: Born Willi , Wekerle Hartmut
Published: February 2007

Primary (1o) and secondary (2o) syngeneic mixed lymphocyte culture (SMLC) reactions in autochthonous murine thymus cell cultures (peanut agglutinin‐unreactive) or syngeneic mixed thymus‐spleen cell cultures were studied. The 1o thymic SMLC responder cells were Thy‐1+, Lyt‐1+, Lyt‐2−. The 1o thymic syngeneic mixed lymphocyte reaction (SMLR) could be inhibited with monoclonal antibodies directed against determinants Ia.m1 and Ia.m6, in the absence of complement.

Positive selection of thymic SMLC cells from 1o cultures was achieved by enriching reactive lymphoblasts on discontinuous Percoll density gradients. The 2o memory populations were obtained by allowing the selected lymphoblasts to revert back to small resting 2o cells in the absence of SMLC stimulation. The thymic 2o SMLC populations were highly enriched in their activity and were almost exclusively specific for self stimulator cells.

The 2o thymic SMLC cells were found to be Thy‐1+, membrane immunoglobulin‐negative, H‐2K/D+, I‐A−, I‐E− and I‐J−. They were hardly lysed by anti‐Lyt‐1 antibodies and not at all lysed by monoclonal antibodies detecting Qat‐4 and 5, and Lyt‐2 antigens, in the presence of complement. Stimulator cells were found in fast‐sedimenting or low‐density fractions of thymus. They expressed H‐2K/D, I‐A‐, and I‐E antigens but lacked membrane immunoglobulin and Thy‐1. Not all I region determinants seemed to be of equal importance in the 2o thymic SMLC: I‐A subregion compatibility between responding and stimulating cells was a minimal requirement for the induction of 2o thymic SMLC responses. Although several relevant anti I‐region antibodies reacted with the stimulator cells in the presence of C, these and other anti‐Ia antibodies varied considerably in their capacity to block 1o and 2o autochthonous thymic SMLR in the absence of complement.

Our finding that the thymus contains the responder as well as the stimulator cells capable of interacting in an autochthonous proliferative reaction will be discussed with regard to its implications for the intrathymic differentiation of T lymphocytes.
Role of Ia antigens in the human autologous mixed lymphocyte reaction
Authors: Mingari Maria Cristina , Moretta Lorenzo
Published: February 2007

The role of Ia antigens in the human autologous mixed lymphocyte reaction (MLR) was analyzed. To do this, different mononuclear cell populations were fractionated according to their Ia antigen expression and used as stimulating cells in autologous MLR. Also examined was the effect of two hybridoma monoclonal antibodies specific for human Ia molecules on the autologous MLR. The results show that the stimulating capacity of peripheral blood mononuclear cells is restricted to Ia‐bearing cells. While peripheral blood T cells are unable to function as stimulating cells, highly purified Ia mixed lymphocyte culture‐activated T cells are very effective. The possibility that Ia molecules are directly involved in the autologous MLR is further substantiated by the strong inhibitory effect of monoclonal anti‐Ia antibodies.
Role of non‐H‐2 antigens in the cytotoxic T cell response to allogeneic H‐2
Authors: Langhorne Jean , Lindahl Kirsten Fischer
Published: February 2007

A limiting dilution assay was used to compare the frequency of cytotoxic T lymphocyte precursors (CTL‐P) which respond to H‐2 antigens presented with additional background differences, with the frequency of CTL‐P which respond to H‐2 antigens on a self background. Individual cultures were divided and assayed for cytotoxic activity on the two targets sharing H‐2, but not the background; no cultures were seen which clearly killed one and not the other, and the same frequency of CTL‐P was measured on target cells that differed from the responder only at H‐2 and on target cells that differed also in the background, irrespective of the background of the stimulator. Thus, the assumption that allospecific cytotoxic T lymphocytes (CTL) recognize H‐2 plus minor histocompatibility antigens does not serve as an adequate explanation for the high frequency of allospecific CTL. The data also suggest that the two allelic forms of β2‐microglobulin do not contribute to the alloantigenic determinant.
The relation of idiotype expression to isotype and allotype in the anti‐p‐azobenzenearsonate response
Authors: Henry Claudia , Lucas Alexander
Published: February 2007

The distribution of idiotype‐positive plaques in mice of various strains injected with T‐independent (TI) and T‐dependent conjugates of p‐azobenzenearsonate (Ars) has been investigated. With maturation of the responses there is a progressive loss of dominance of the major cross‐reactive idiotype (CRI) in A/J and C.AL‐20 mice. The extremes are represented by the predominantly CRI+ IgM plaque response to a single injection of the TI antigen, Ars‐coupled Brucella organisms (Ars‐Br), and the low frequency of CRI+ plaques in the polyisotypic response elicited by Ars‐KLH (keyhole limpet hemocyanin) in adjuvant. The secondary response to Ars‐Br was characterized by an intermediate display of idiotype‐positive plaques in IgM, the IgG subclasses and IgA. Detailed analyses of the distribution of CRI+ plaques between isotypes in 60 mice hyperimmunized with Ars‐KLH revealed that the expression of idiotype in any of the IgG subclasses and IgA was constant and independent. This is interpreted to indicate random assembly of VH with Cγ and Cα genes during the switch.

BALB/c and C3H mice also express a predominant idiotype during primary and secondary responses to Ars‐Br as detected by our heterologous anti‐A/J CRI serum. These strains only very rarely maintain the idiotype after hyperimmunization with Ars‐KLH. We conclude that hyperimmune responses which probably involve multiple modes of regulation give a poor indication of the germ‐line V gene repertoire.
Phenotype of human T helper and suppressor cells in an in vitro specific antibody response
Authors: Callard Robin E. , Smith Caroline M. , Beverley Peter C. L.
Published: February 2007

Monoclonal anti‐human T cell antibodies have been used to identify cells which provide help for an in vitro specific antibody response to influenza virus and also those which suppress the response of allogeneic peripheral blood mononuclear cells. The helper cells carry antigens defined by the Leu 3a and OKT4‐antisera, whereas the suppressor cells are predominantly Leu 2a‐ and OKT8‐positive. Help and suppression in this secondary in vitro antibody response are therefore provided by antigenically distinct T cell subsets.
Detection of Thy‐1, T‐200, Lyt‐1 and Lyt‐2‐bearing cells in the developing lymphoid organs of the mouse embryo in vivo and in vitro
Authors: Van Ewijk Willem , Jenkinson Eric J. , Owen John J. T.
Published: February 2007

The appearance of cell membrane antigens on lymphoid cells of the embryonic thymus in vivo and in vitro using monoclonal antibodies in immunoperoxidase tests on frozen sections and in two‐color immunofluorescence tests on cell suspensions was studied. It was shown that cells are heterogeneous with respect to Lyt antigen expression from the earliest stages of ontogeny. Thus, after 16 days gestation, some cells are Lyt‐1+2−, others are Lyt‐1−2+ and some are Lyt‐1+2+. However, for various reasons which are discussed, we hesitate to suggest that this finding demonstrates independent derivation of the various T cell subsets.

In the absence of cell migration, organ cultures of embryonic thymus generate enriched populations of Lyt‐1+2− and Lyt‐1−2+ cells, i.e. cells with functional “mature” phenotypes. It was not found that cells bearing T cell antigens are generated in organ cultures of fetal liver and spleen. This result argues against the thymus‐independent generation of T cells in these organs.
Hapten‐specific responses to the phenyltrimethyl‐amino hapten.I. Evidence for idiotype‐anti‐idiotype interactions in delayed‐type hypersensitivity in mice
Authors: Jayaraman Sundararajan , Bellone Clifford J.
Published: February 2007

The delayed‐type hypersensitivity (DTH) reaction to the phenyltrimethylamino (TMA) hapten in mice has been investigated. TMA‐derivatized syngeneic spleen cells (TMA‐SC) administered S.C. in several strains of mice consistently evoked DTH reactivity, as measured by footpad swelling after challenge with the diazonium salt of TMA. DTH could be induced by low levels of anti‐idiotypic antisera (anti‐Id) in lieu of antigen. The DTH reaction induced by either mode was hapten‐specific, could be transferred into naive recipients by viable lymph node cells but not with serum from immune mice and was not influenced by cyclophoshamide pretreatment. Unlike TMA‐SC which induced DTH in all of the strains of mice tested, anti‐Id induced DTH only in strains of the Igh‐1e allotype. Positive DTH reactions were induced by anti‐Id in the C57.Ige strain (H‐2b, Igh‐1e) but not in its allotype‐congenic partner C57BL/6J (H‐2b, Igh‐lb). Interestingly, this reaction could be suppressed if relatively high amounts of anti‐Id were inoculated i.v. just prior to antigen challenge. In addition, the administration of anti‐Id 1 h prior to antigen challenge in TMA‐SC‐sensitized mice significantly blocked the DTH reaction only in the Igh‐1e strains. These results demonstrate that the induction and abrogation of TMA‐specific DTH by anti‐Id is linked to the IgCH locus.
Antigen‐dependent, H‐2‐restricted cytolytic and noncytolytic T cell lines with specificity for minor histocompatibility antigens
Authors: Pauli Raimund Di , Opalka Bertram
Published: February 2007

Several cloned T cell lines were isolated from primed mixed lymphocyte cultures immunized against minor histocompatibility antigens. These lines were selected with irradiated stimulator cells as antigen and require restimulation at intervals to keep growing. They are responsive, as measured by proliferation, to interleukin 2 (T cell growth factor) but cannot be grown in it continuously.

These T cell lines have either the H‐2d or H‐2k haplotype. They all show exquisite H‐2 restriction and minor histocompatibility antigen specificity. We did not observe any alloreactivity on 8 different H‐2 haplotypes. For the H‐2k T cell lines, the restriction element could be mapped to either the K or D end of the H‐2 complex. No I‐A‐restricted cell line was found.

It is of interest that all these T cell lines need the presence of T cells in the irradiated stimulator cell population. This suggests a more complex interaction between irradiated stimulators and responder T cells than just H‐2K‐ or D‐restricted antigen interaction. This recognition, though necessary, does not seem sufficient to induce the T cell clones to proliferate.
Constitutive interleukin 2 production by the JURKAT human leukemic T cell line
Authors: Pawelec Graham , Borowitz A. , Krammer Peter H. , Wernet Peter
Published: February 2007

Interleukin 2 (IL2) is a lymphokine produced from phytohemagglutinin (PHA)‐stimulated peripheral blood mononuclear cells and characterized biologically by its ability to maintain the in vitro proliferation of activated T cells. In a search for a convenient alternative source of biologically active human IL2, cells from the five established T cell lines, MOLT4, HSB2, CCRF‐CEM, RPMI1301 and JURKAT were cultured at high concentrations for 18‐36 h (induction cultures), and their cell‐free supernatants thereafter screened on IL 2‐dependent cultured human and mouse T cells. MOLT4, HSB2, RPMI1301, and CCRF‐CEM all failed to produce detectable levels of IL2. Of the three JURKAT cell lines obtained from different sources, one, designated JMN, produced high levels of IL2 activity. A second, JM, failed to produce any IL2, while the third, JHAN, produced intermediate levels. Stimulation of the IL2‐producing JMN or JHAN variants with PHA, the phorbol diester 12‐0‐tetradecanoyl‐phorbol‐13‐acetate (TPA), or both PHA and TPA together, resulted in an apparent increase of IL2 activity in the culture supernatant when assayed by a short‐term tritiated thymidine incorporation test. However, both PHA and TPA added directly to the test cells caused substantial thymidine incorporation. Moreover, the nonproducer line JURKAT‐JM could not be converted to an IL2 producer by stimulation with PHA, TPA, or both. When JMN supernatants were used to support actual long‐term growth and cloning of T cells in limiting dilution, the constitutively produced IL2 was superior to that produced after PHA and/or TPA stimulation. Addition of TPA, but not of PHA, to lectin and TPA‐free JMN IL2 resulted in a decreased ability of such supernatants to support clonal T cell growth, suggesting that TPA had a growth‐inhibiting effect. These results show that the continuously growing JURKAT‐JMN cell line could provide a suitable source of mitogen‐free human IL2.
T cell idiotypes recognizing self‐major histocompatibility complex molecules: H‐2 specificity, allotype linkage, and expression on functional T cell populations
Authors: Nagy Zoltan A. , Elliott Bruce E. , Carlow Douglas A. , Rubin Bent
Published: February 2007

An anti‐idiotypic serum (antiserum 5936, B. Rubin et al., J. Exp. Med. 1979. 150: 307) was used to demonstrate receptor sites for self‐major histocompatibility complex (MHC) antigens on T lymphocytes. The antiserum was raised by injecting rabbits tolerant to mouse Ig with a B6 anti‐CBA (anti‐H‐2k) alloantibody. It recognized a large proportion of T cells from H‐2k strains carrying the b, c, d or e allele at the Igh‐1 locus, but only a few T cells from H‐2k strains with Igh‐1 alleles a, f and j. Allotype linkage of the 5936 idiotype was also demonstrated by segregation analysis. The antiserum did not recognize either H‐2k B cells or T cells from other H‐2 haplotypes despite the presence of a permissive Igh‐1 allele. The 5936 idiotype was found to be associated with several different antigen specificities, indicating that it is not located on the binding site for foreign antigen. Furthermore, the 5936 antiserum inhibited the binding of soluble Ik antigens by H‐2k, Igh‐1b, T cells, and, in the presence of complement, eliminated T cells responding to different antigens in an I‐Ak‐restricted fashion. Collectively, the data indicate that the structure bearing the 5936 idiotype is a receptor for I‐Ak antigens, expressed by strains carrying the I‐Ak allele and a permissive allele at the Igh‐1 locus. The relevance of this finding to the MHC‐restricted recognition of antigens by T cells is discussed.
Immunogenic variants obtained by mutagenesis of mouse mastocytoma P815. IV. Analysis of variant‐specific antigens by selection of antigen‐loss variants with cytolytic T cell clones
Authors: Maryanski Janet L. , Boon Thierry
Published: February 2007

Mouse mastocytoma P815 tumor cell variants that express new individual antigens were subjected to immunoselection in vitro with specific cytolytic T lymphocyte (CTL) clones. From one variant (P35) a number of resistant clones were isolated after a single‐step selection. These immunoselected clones (P35.iscA−) proved to have acquired a stable and complete resistance to lysis by the selecting CTL, but remained sensitive to lysis by a CTL clone that recognizes a common P815 antigen. However, when these P35.iscA‐ clones were used to stimulate in vitro spleen cells from mice immunized with variant P35, the cytolytic activity was significantly higher on P35 and P35.iscA− targets than on the original P815 clone (P1). This indicated that P35.iscA‐cells, which had lost a P35‐specific determinant (P35A), had nevertheless retained another P35‐specific determinant (P35B). CTL clones directed against the residual P35B determinant were then isolated. When P35 cells were submitted to selection with anti‐P35B CTL, resistant clones (P35.iscB−) were obtained that were still lysed by anti‐P35A and anti‐P815 CTL clones. Tum− variant P35 therefore carries at least two specific determinants that can be lost independently. These results show the possibility of using selection with CTL clones to separate different components of complex cell surface antigens.

The correlation between antigen expression and tumorigenicity was also examined. Antigen‐loss P35.iscA− clones were found to be more tumorigenic than variant P35 which has a greatly reduced tumorigenic capacity compared to the original P815 tumor. This correlation suggests that the P35 determinant that was no longer expressed by the P35.iscA− clones is recognized on the original P35 tum− variant as a tumor rejection antigen.
Human large granular lymphocytes and natural killing: Ultrastructural studies of strontium‐induced degranulation
Authors: Neighbour P. Andrew , Huberman Harris S. , Kress Yvonne
Published: February 2007

Large granular lymphocytes (LGL) are a subpopulation of human peripheral blood mononuclear cells believed to contain the mediators of spontaneous cytotoxicity or natural killing. In the present study, the mononuclear cells were enriched for LGL by differential density centrifugation on Percoll gradients and examined by transmission electron microscopy. The ultrastructure of LGL and of their binding interaction with natural killer‐susceptible target cells (K562) is described in detail. Some morphological similarity between LGL and cells of a myelocytic origin was observed. Studies reported elsewhere have shown that Sr2+, an alkaline earth ion known to degranulate granulocytes, inhibits NK cell function. Comparison of the morphology of control and Sr2+‐treated LGL showed that Sr2+ caused several characteristic changes in LGL ultrastructure and, indeed, led to their degranulation. The recovery of natural killer function seen following in vitro culture of Sr2+‐treated effector cells was accompanied by the reappearance of typical intracytoplasmic granules. These data strongly suggest that the granules of LGL are required for and, perhaps, involved in natural killer‐mediated cytolysis.
Polyclonal effect of HgCl2 in the rat, its possible role in an experimental autoimmune disease
Authors: Hirsch Francois , Couderc Jacques , Sapin Catherine , Fournie Gilbert , Druet Philippe
Published: February 2007

Mercuric chloride induces an immune glomerulonephritis in Brown‐Norway (BN) but not in Lewis (LEW) rats. Injection of HgCl2 into BN rats regularly produced a transient appearance of plaque‐forming cells (PFC) of anti‐2,4,6‐trinitrophenyl and anti‐sheep red blood cell specificity and circulating anti‐single‐stranded DNA antibodies. Addition of HgCl2 to spleen cell cultures from BN rats induced an increase in anti‐trinitrophenyl PFC and reverse PFC. This effect was no longer observed when nylon wool column‐depleted or anti‐Thy‐1 antiserum‐treated spleen cells were cultured in the presence of HgCl2. These data suggest that HgCl2 acts as a polyclonal activator on spleen cells in BN rats, but not on isolated B lymphocytes. In contrast, no effect of HgCl2 on immunoglobulin production was observed in LEW rats. Since polyclonal activation and immune‐type nephritis are both seen in BN but not in LEW rats, polyclonal activation may participate in the pathogenesis of the HgCl2‐induced autoimmune disease of BN rats.
H‐2‐restricted T‐B cell interactions involved in polyspecific B cell responses mediated by soluble antigen
Authors: Ratcliffe Michael J. H. , Julius Michael H.
Published: February 2007

Maturation of polyspecific B cells to Ig secretion was induced in response to the interaction of helper T cells with soluble antigen. The in vitro propagated, keyhole limpet hemocyanin (KLH)‐primed C57BL16 T cells used in these experiments proliferated in response to antigen presented on I‐A‐compatible antigen‐presenting cells and were depleted of alloreactive cells. These T cells induced a strong polyspecific plaque‐forming cell response from normal C57BL/6 B cells over a wide range of KLH concentrations (100 μg/ml to 0.01 μg/ml). Culture conditions were established whereby H‐2‐restricted T cell‐macrophage interactions were nonlimiting, allowing a direct analysis of H‐2‐restricted T‐B cell interactions involved in polyspecific B cell induction.

The requirements for B cell induction/amplification were dependent on the size of the responding B cell population. Small B cells were activated only at high concentrations of KLH and required a direct H‐2‐restricted interaction with KLH‐primed helper T cells. In contrast, large B cells were induced/amplified over the full range of KLH concentrations tested in an H‐2‐unrestricted manner, limited only by the H‐2‐restricted, antigen‐dependent activation of T helper cells. The requirement for high antigen concentration in the activation of small B cells is proposed to reflect a requirement for antigen binding to the B cell surface via nonspecific interactions. This binding was not in itself stimulatory, but expression of antigen in conjunction with B cell surface Ia antigens provided a focus for a direct interaction with Ia‐restricted, antigen‐specific T helper cells (or factors). In contrast, the H‐2‐unrestricted induction/ amplification of large B cells was mediated solely as a consequence of the helper T cell activation which occurred at the lowest concentrations of KLH tested. T helper cell activation is proposed to lead to the production of non‐antigen‐specific, non‐Ia‐restricted factors supporting the continued growth of blasted B cells.

Thus, while an H‐2‐restricted T cell‐macrophage interaction is an obligate requirement for polyspecific B cell responses, the requirement for a direct H‐2‐restricted T‐B cell interaction varies with the pre‐existing state of activation of the responding B cell population.
The gene, MIC4, which controls expression of the antigen defined by monoclonal antibody F10.44.2, is on human chromosome 11
Authors: Goodfellow Peter N. , Banting George , Wiles Michael V. , Tunnacliffe Alan , Parkar Mohamed , Solomon Ellen , Dalchau Rosemarie , Fabre John W.
Published: February 2007

The monoclonal antibody, F10.44.2, is directed against a human antigenic determinant of restricted tissue distribution. In this report it is shown that this determinant is coded for by a gene, MIC4, which is on human chromosome 11, as shown by its reactivity with a panel of somatic cell hybrids. Synteny with an antigen recognized by another monoclonal antibody, W6/34, is demonstrated by hybrid and fluorescence‐activated cell sorter analysis, although it is clear from absorption analysis that the determinants involved are on different molecules.
Immune recognition of tumor cells in vivo. I. Role of H‐2 gene products in T lymphocyte activation against minor histocompatibility antigens displayed by adenocarcinoma cells
Authors: Forni Guido , Landolfo Santo , Giovarelli Mirella , Whitmore Alan C. , Herberman Ronald B.
Published: February 2007

Challenges from ADK‐1t adenocarcinoma cells of BALB/c (H‐2d, Mlsb) mouse origin are rejected by DBA/2 (H‐2d, Mlsa) mice on the basis of differences in a limited number of minor histocompatibility antigens. This T lymphocyte‐dependent reaction is highly specific, and efficiently triggered only by Ia+ leukocytes infiltrating the tumor mass. ADK‐1t challenges depleted of Ia+ infiltrating BALB/c leukocytes grow and kill DBA/2 mice, whereas the simultaneous injection of Ia+ inactivated BALB/c leukocytes induces tumor rejection. The expression of Mlsb‐incompatible determinants on the Ia+ BALB/c leukocyte membrane is irrelevant in the induction of this efficient T lymphocyte reaction against BALB/c minor histocompatibility antigens. By contrast, a critical requirement is H‐2 matching between the Ia+ leukocytes and the recipient mice at the inductive phase of the reaction.
Cytotoxic T lymphocyte lines reactive against murine plasmacytoma antigens: Dissociation of cytotoxicity and Lyt‐2 expression
Authors: Giorgi Janis V. , Zawadzki Jerome A. , Warner Noel L.
Published: February 2007

The relationship between cell surface antigen expression and function in cytotoxic T cells directed against a non‐H‐2‐restricted plasmacytoma antigen was examined using Lyt−2− variants of a continuous T cell line. This cytotoxic cell line originally had expressed Lyt‐2 on all the cells as detected by flow microfluorometry, but after several months of culture, Lyt−2− variants spontaneously developed. Using cell sorting and limiting dilution cloning, Lyt−2− and Lyt−2+ cell lines were obtained, cultured and analyzed. These analyses indicated that such cytotoxic cells had similar activity regardless of Lyt‐2 phenotype. This observation supports the concept that the Lyt‐2 molecule is not obligatory for recognition and killing by cytotoxic T cells and emphasizes the need to clarify the precise relationship between cell surface phenotype and T cell function.
Differential expression and serologically distinct subpopulations of human Ia antigens detected with monoclonal antibodies to Ia alpha and beta chains
Authors: Guy Keith , Van Heyningen Veronica , Cohen Brian B. , Deane David L. , Steel C. Michael
Published: February 2007

Studies with two monoclonal antibodies (DA6.147 and DA6.231) which react, respectively, with isolated human Ia α and β chains are reported. Both antibodies detect epitopes expressed on all DR‐heterozygous and DR‐homozygous cell lines tested (n = 17) and bind to the Epstein‐Barr virus‐negative cell line Ramos. Ia subunit specificity of the antibodies was determined by an adaptation of an electroblot technique which transfers separated la chains from polyacrylamide gels to nitrocellulose paper. In radioimmunobinding assays, peripheral blood B cell‐enriched fractions, phytohemagglutinin‐activated T cells and pokeweed mitogen‐activated cells gave strong reactions with DA6.231 (anti‐Ia β). In contrast, DA6.147 (anti‐Ia α) reacted only weakly, if at all, with peripheral B cells, pokeweed mitogen blasts and activated T cells. However, both antibodies bound to isolated Ia from activated T cells and peripheral B cells after Nonidet‐P40 solubilization of the cells and DA6.147+ antigens could be found in the cytoplasm of activated T cells by indirect immunofluorescence techniques. Results of serological inhibition procedures following fractionation of lymphoblastoid cell lysates on monoclonal antibody affinity columns showed that the DA6.147 α chain epitope is carried on only a minor subpopulation of human Ia.
Delayed‐type hypersensitivity induced in immunodeficient mice with syngeneic modified self antigens: a suggestive model of autoimmune response
Authors: Tarcic Nora , Naor David
Published: February 2007

Previous studies suggested that trinitrophenyl (TNP)‐modified syngeneic red cells induced humoral autoimmune response in mice with defective T cell function but not in normal mice. The ability of modified self antigen to induce autoimmune response in immunodeficient mice was further explored using the delayed‐type hypersensitivity (DTH) as an assay system. Mice were immunized with syngeneic TNP‐modified spleen cells (TNP‐SC) and challenged by syngeneic nonmodified conconavalin A (Con A) or lipopolysaccharide (LPS)‐stimulated spleen cells injected into their footpads. The DTH response was assessed 24, 48 and 72 h later by measuring the footpad swelling and was transferred to naive recipients with enriched T cells from TNP‐SC‐immunized irradiated A mice but not with serum or non‐T cells. Adult thymectomized, X‐irradiated (250 rds) and cyclophosphamide‐treated mice injected with syngeneic TNP‐SC generated a DTH response when subsequently challenged with syngeneic lymphoblasts (induced with Con A or LPS) but not when challenged with allogeneic blast cells. In contrast, normal mice treated in a similar manner exhibited a much less significant DTH response. SC incubated 1 to 3 h with Con A failed to elicit the DTH response of immunodeficient mice previously injected with TNP‐SC. Both lymphoblasts that were induced in vitro with Con A diluted in fetal calf serum or in normal mouse serum‐containing media, and lymphoblasts that were induced in vivo by interleukin 2 elicited DTH responses in X‐irradiated, TNP‐SC immunized mice. The syngeneic DTH response of the immunodeficient mice injected with TNP‐SC was abrogated when they were simultaneously transplanted with syngeneic SC or nylon wool‐passed syngeneic SC. If the transplanted splenocytes had been treated with anti‐Thy‐1 antiserum and complement they failed to abrogate the syngeneic‐DTH response of the above mentioned mice. This result suggests that suppressor cells are programmed to control the autoimmune response induced with modified self antigens.
Characterization and expression of H‐2I region gene products on bone marrow‐derived macrophages
Authors: Schook Lawrence B. , Bingham Eve L. , Gutmann David H. , Niederhuber John E.
Published: February 2007

Antigen‐presenting macrophages (MΦ) were derived from day 7 cultures of bone marrow stem cells using L cell conditioned medium. The adherent bone marrow‐derived macrophages (BMMΦ) were 100% esterase‐positive, 95% positive for C3 receptors, 93% positive for Fc receptors, and 95% actively phagocytic. Indirect immunofluorescence using anti‐Ia monoclonal antibodies resulted in 60% Ia‐positive BMMΦ on day 7 of stem cell culture. BMMΦ could stimulate mixed lymphocyte reaction (MLR) proliferation across an I‐A subregion difference, but not across I‐J subregion differences. This contrasted with splenic MΦ which stimulated MLR proliferation across both an I‐A and I‐J subregion difference. The apparent lack of I‐J subregion determinants on BMMΦ correlated with their ability to function as antigen‐presenting cells. In these experiments, BMMΦ effectively reconstituted the trinitrophenyl‐specific IgM plaque‐forming cell (PFC) response of B cells but not the primary burro red blood cell (BRBC)‐specific IgM‐PFC response of MΦ‐depleted spleen cells. When BMMΦ were added to BRBC‐primed T and B cells, they reconstituted the secondary IgG PFC response to levels obtained using splenic MΦ. These experiments relate the differential expression of H‐2I region determinants on antigen‐presenting cells with their functional capacity.
20α‐Hydroxysteroid dehydrogenase expression in hemopoietic cell cultures and its relationship to interleukin 3
Authors: Garland John M. , Dexter T. M.
Published: February 2007

Expression of 20α‐hydroxysteroid dehydrogenase (20α‐SDH) has been investigated in long‐term bone marrow cultures derived from normal and nude mice in the presence of horse serum and hydrocortisone. 20α ‐SDH expression rises markedly in the adherent cells derived from normal bone marrow. Early (1‐5 days) lipid profiles are similar to those seen in T cells, but at later times (6‐14 days) stromal‐type lipid patterns dominate. Similar culture of fetal liver and nu/nu bone marrow cells shows rises in 20α ‐SDH expression, in situations where T cells are notably absent. The expression of 20α‐SDH is not associated with detectable endogenous production of “interleukin 3” activity, and although addition of “IL 3” to bone marrow cultures increases the levels of 20α ‐SDH, this is associated with granulopoiesis rather than lymphoid development.
Influence of the nude and X‐Iinked immune deficiency genes on expression of × and λ light chains
Authors: Burkly Linda C. , Zaugg Robert , Eisen Herman N. , Wortis Henry H.
Published: February 2007

The relative amounts of Igx and Igλ1 anti‐2,4‐dinitrophenyl antibodies were measured at various times after immunizing mice with prototype thymus‐dependent (TD), thymus‐independent type 1 (TI‐1) and thymus‐independent type 2 (TI‐2) antigens. Similar amounts of Igλ1 were produced after TD and TI‐2 immunization and somewhat less was produced after a TI‐1 stimulus. In contrast, Igx levels were much greater after TD than after TI‐1 or TI‐2 antigen. The amount of light chain isotype produced appeared to depend on the molecular form in which the hapten was presented, although possible adjuvant effects were not ruled out.

Levels of Igx and Igλ present in nonimmune sera were measured in normal, xid and nude mice. The x/λ, ratio was higher in xid than in normal mice and the difference was demonstrated by F1 analysis to be due to an X‐linked gene. Conversely, the x/λ ratio was lower in nude than in normal mice. This was true for the CBA/Tufts (Ighj), CBA. Ighb and C57BL/10 strains. However, there were no detectable differences in the relative frequencies of surface Igx‐ and Igλ ‐bearing B cells in adult CBA/Tufts, CBA/N and nude mice. Hence, serum ratios may reflect differences at the level of B cell triggering.

Two possible explanations for these differences are discussed. Igx and Igλ may be expressed on functionally distinct B cell subsets. (For instance Igλ ‐producing cells might be readily triggered by T1 antigens whereas Igx‐producing cells are more dependent on T cell signals. Such functional subsets could be determined by light chain expression). Alternatively, cells producing Igx antibody are selected for because they have a higher affinity for antigen. If so, triggering of cells producing high affinity Igx or their subsequent selection is T cell‐dependent.
Role of veiled cells in lymphocyte activation
Authors: Knight Stella C. , Balfour Brigid M. , O'brien Jacqueline , Buttifant Lindy , Sumerska Tatjana , Clarke John
Published: February 2007

Peripheral blood lymphocytes from normal rabbits or from rabbits hyperimmunized with human immunoglobulin were cultured in 20‐μl hanging droplets. The cultures were stimulated with concanavalin A or, in the case of cells from sensitized animals, with human immunoglobulin.

The addition to the cultures of small numbers of autologous or allogeneic veiled cells separated from afferent lymph increased the responses to low doses of the stimulants, particularly when the cells were cultured at low cell densities or for short periods of time. At high cell densities or at longer periods of culture, stimulation occurred in the absence of added veiled cells and was associated with clumping of the lymphoid cells and development of cells which morphologically resembled veiled cells found in afferent lymph. The enhanced responses upon addition of small numbers of veiled cells were also correlated with the formation of lymphoid aggregates which were frequently held together by the elongated processes of a single veiled cell. The observations support the view that the veiled cells are lymph‐borne precursors of dendritic cells in the lymph nodes. This may provide an in vitro model for the cellular relationships which occur in paracortical cords of lymph nodes following antigenic stimulation.
Immature thymocytes isolated using a sialic acidspecific lectin are unresponsive to concanavalin A
Authors: Herron Lynne R. , Abel Carlos A. , Wall Jennifer Vander , Campbell Priscilla A.
Published: February 2007

Mouse thymocytes, which are approximately 90% immature cortical cells, are low in surface sialic acid when compared with more mature cortisone‐resistant, presumably medullary, thymocytes and peripheral T lymphocytes. Thus, medullary thymocytes bind and are agglutinated by the N‐acetylneuraminic acid‐specific lectin, lobster agglutinin 1 (LAg1), whereas cortical thymocytes are not agglutinated by this lectin. It is demonstrated herein that mouse cortical thymocytes, purified using LAg1, do not respond to the mitogenic effects of concanavalin A (Con A). The lack of response to this lectin is not due to depletion of macrophages, since addition of macrophages does not restore the response. Populations of LAg1‐negative thymocytes can be made to respond weakly to Con A by the addition of interleukin 2, but this response appears to be due to the presence of a few contaminating LAg1‐binding thymocytes since it is abolished by treatment of the cells with rabbit anti‐LAg1 serum plus complement. Therefore highly purified cortical thymocytes not only cannot respond to Con A, but also they cannot be induced to respond by the addition of the T cell growth factor, interleukin 2. Thymocytes isolated by a single criterion, that is by virtue of their low amount of surface sialic acid, appear to be a truly immature population of thymocytes.
Distinct HLA‐DR epitopes and distinct families of HLA‐DR molecules defined by 15 monoclonal antibodies (mAb) either anti‐DR or allo‐anti‐Iak crossreacting with human DR molecule. I. Cross‐inhibition studies of mAb cell surface fixation and differential binding of mAb to detergent‐solubilized HLA molecules immobilized to a solid phase by a first mAb
Authors: Rebai Najet , Malissen Bernard , Pierres Michel , Accolla Roberto S. , Corte Giorgio , Mawas Claude
Published: February 2007

A series of HLA‐DR‐reactive mouse anti‐human B cell or anti‐Ia monoclonal antibodies (mAb) have been used to explore the serological complexity of human class II antigens at the determinant level, using two techniques: (a) cross antibody‐binding competitor assays using 125I‐labeled and ‐unlabeled mAb were performed to study the topological organization of the corresponding determinants to determine epitopic clusters recognized by this collection of mAb and (b) differential reactivity of mAb to detergent‐solobilized solid‐phase‐immobilized HLA‐DR molecules to determine epitopes expressed on identical DR isotypes. The fifteen mAb could be classified according to the first technique as falling into three different epitopic clusters. Using the second technique, we were able to define at least two independent molecular subsets, one co‐expressing two of the three epitopic clusters and the second expressing only the third one. We could not formally identify molecular subsets expressing only one of the first two clusters, using the second technique.

The precise serological mapping of the determinants recognized by various anticlass II mAb should prove very useful if such mAb were to be introduced in anticlass II‐specific T cell clone blocking experiments. We anticipate that some of them should facilitate the correlation at the clonal level between the T cell repertoire and the epitopes or molecular subsets defined by these mAb. However, within mAb belonging apparently to a same cluster, some could mediate different biological effects.
Autonomously proliferating K/D‐restricted cytolytic T cell clones
Authors: Von Boehmer Harald , Turton Katrin
Published: February 2007

K/D‐restricted male‐specific cytolytic T lymphocytes (CTL) have been cloned and assayed for male‐specific proliferation in the absence of exogenous interleukin 2 (T cell growth factor). The majority of freshly cloned CTL proliferate in response to cell‐bound antigen. The clones lose their proliferative potential after growing for three weeks in media containing IL2.
Simultaneous absence of the human IgG1, IgG2, IgG4 and IgA1 subclasses: Immunological and immunogenetical considerations
Authors: Lefranc Gérard , Chaabani Hassen , Van Loghem Erna , Lefranc Marie‐Paule , De Lange Gerda , Helal Ahmed‐Noureddine
Published: February 2007

Simultaneous absence of the IgG1, IgG2, IgG4 and IgA1 immunoglobulins has been unambiguously demonstrated in a healthy 75‐year‐old woman by testing for allotypes, isoallotypes and for isotypes of these four subclasses. Only IgM, IgD, IgG3, IgA2 and IgE were present. The IgG3 levels were significantly increased. Family investigation showed inheritance of a haplotype Gm−;−;b A2m2. This person is homozygous for an extensive DNA deletion including the Cγ1, Cγ2, Cγ4 and Cα1 genes.