bluuebunny/crossref_metadata_2025 huggingface dataset:
Species‐restricted effects of human and mouse lymphokines on macrophages
Authors: Tagliabue Aldo , Mantovani Alberto , Boraschi Diana , Herberman Ronald B.
Published: February 2007

Lymphokines produced by antigenic or mitogenic stimulation of human, guinea pig and mouse lymphocytes were tested for their effects on monocytes or macrophages of the same and heterologous species, to determine whether there is any species restriction in their reactivity. Supernatants from lymphocyte cultures were tested for migration inhibitory activity in an indirect agarose microdroplet assay and for their ability to augment cytolytic activity of macrophages or monocytes in a [3H] thymidine‐release assay. Supernatants of human peripheral blood mononuclear cells, stimulated with phytohemagglutinin or purified protein derivative of tuberculin (PPD) were able to strongly inhibit the migration of human monocytes and guinea pig peritoneal exudate cells (PEC), but had no detectable effect on mouse PEC. The human Supernatants could also significantly augment the cytolytic activity of human monocytes, but had no effect on cytotoxicity by mouse peritoneal macrophages. Conversely, Supernatants of PPD‐stimulated spleen cells from mice immune to bacillus Calmette‐Guérin (BCG) strongly inhibited the migration of, and significantly augmented cytolysis by, mouse PEC, but had no detectable effects on human monocytes. Moreover, Supernatants of concanavalin A‐stimulated lymph node cells from guinea pigs inhibited the migration of guinea pig PEC and human monocytes, but had no effects on mouse PEC. The migration inhibitory effects of the human and mouse Supernatants did not appear to be mediated by interferon (IF), since partially purified type‐1 IF had no detectable effect. In addition, Supernatants of human lymphocytes stimulated by Corynebacterium parvum strain 5888, that induced little or no IF, were able to inhibit the migration of, and augmented cytolysis by, human monocytes. These C. parvum super‐natants also showed migration inhibitory activity on mouse PEC but did not induce cytolytic activity in these cells'.
Gene complementation in the T lymphocyte proliferative response to poly(Glu56Lys35Phe9)nFunctional evidence for a restriction element coded for by both the I‐A and I‐E subregions
Authors: Schwartz Ronald H. , Chen Chuan , Paul William E.
Published: February 2007

The T lymphocyte proliferative response to poly(Glu56Lys35Phe9)n (GLΦ) is under the control of two immune response genes, Ir‐GLΦ‐β and Ir‐GLΦ‐α, mapping in the I‐A and I‐E/C subregions of the major histocompatibility complex, respectively. Previous studies have demonstrated that in order to generate a response to GLΦ, both gene products must be expressed in the antigen‐presenting cell (APC) but that neither responder allele has to be present in the responding T lymphocyte, provided that the T cell has matured in a responder environment. These results suggested that both gene products function as restricting elements in GLΦ presentation by APC. In this report, we provide further evidence for this model from experiments designed to test histocompatibility restrictions in antigen presentation at the I‐E/C subregion. Genetic identity at the I‐A subregion between T cells and APC was required for GLΦ presentation. To assess the requirements at I‐E/C, B10. A(5R) T cells (I‐Ab, I‐Ek) primed to GLΦ were stimulated in vitro with GLΦ‐pulsed spleen cells from F1 hybrids between C57BL/10 (B10: I‐Ab, I‐Eb) which made the cells compatible at I‐A, and a variety of B10 congenics bearing other H‐2 haplotypes. Although none of the parental spleen cells could present GLΦ to B10.A(5R) T cells, spleen cells from F1 hybrids between B10 and strains possessing H‐2I of k, d, p and r presented GLΦ, whereas hybrids with strains possessing H‐2I of f, q and s failed to present. This pattern of complementation for GLΦ presentation could not be explained on the basis of the responder status of the I‐E/C donating parental haplotypes nor by invoking inhibitory stimuli from mixed lymphocyte reactions induced by the Fl APC. Rather, the pattern correlated with the presence of the serologic marker Ia.7 coded for by the I‐E subregion of the complementing parental haplotype and the possession of an I‐E‐encoded a chain which has been shown by peptide mapping to be very similar in strains bearing the k, d, p and r haplotypes. These results suggest that the restriction element involved in the presentation of GLΦ to B10.A(5R) T cells is composed of a β chain encoded in I‐Ab and an a chain encoded in I‐E for which the allelic products of the k, d, p and r haplotypes are functionally equivalent. This correlation between structure and function represents the strongest evidence so far that Ia antigen‐bearing molecules are the Ir gene products.
Monoclonal antibody to a human leukocyte‐specific membrane glycoprotein probably homologous to the leukocyte‐common (L‐C) antigen of the rat
Authors: Dalchau Rosemarie , Kirkley Jean , Fabre John W.
Published: February 2007

The monoclonal antibody (F10–89–4) described in this study recognizes an antigen which by quantitative absorption analysis is absent from human brain, kidney, liver, heart, erythrocytes, platelets and normal serum, but is present on spleen, lymph node, chronic lymphatic leukemia cells, bone marrow, thymus and granulocytes at a ratio of 1 : 1 : 0.8 : 0.3 : 0.3 : 0.1, respectively. Analysis with the fluorescence‐activated cell sorter showed that 100% of thymocytes, lymph node lymphocytes, blood mononuclear cells and granulocytes carry the antigen, while 83% of bone marrow cells are positive. There was marked heterogeneity in the amount of labeling of thymocytes, with 3 major peaks. There was also heterogeneity of labeling of blood mononuclear cells and lymph node lymphocytes, with a weakly staining hump containing approximately 20% of the cells in the case of lymph node lymphocytes. Double labeling experiments demonstrated that the weakly staining cells of blood and lymph node were B lymphocytes, while frozen sections of thymus showed that the antigen was expressed most weakly in subcapsular cortical thymocytes, and most strongly on medullary thymocytes. Biochemical studies established that the antigen bound to lentil lectin columns, and sodium dodecyl sulfate polyacrylamide gel electrophoresis studies using NaB3 H4‐labeled blood mononuclear cells established that the antigen was a major glycoprotein of lymphocytes, and that its molecular weight was in the region of 190 000 to 215 000.
Presence of T145 on cytolytic T cell lines and their lectin‐resistant mutants
Authors: Conzelmann Andreas , Pink Richard , Acuto Oreste , Mach Jean‐Pierre , Dolivo Souzan , Nabholz Markus
Published: February 2007

Murine cytolytic T cell lines have been analyzed for the expression of two surface glycoproteins called T 145 and T 130. T 145, known to be expressed by activated cytolytic T cells, is also expressed by such lines, but T 130, which has been described as a universal T cell marker, is not. Our results suggest a structural relationship between T 145 and T 130. Vicia villosa lectin, which binds selectively to T 145 of activated T cells and which is cytotoxic for cytolytic T cell lines, has been used to select lectin‐resistant mutants from these lines. Five independent lectin‐resistant mutants have been obtained. All of them are cytolytically active, bind up to 100‐fold less lectin than the parental lines, but still express T 145 or a closely related glycoprotein.
Cellular mechanisms of restricted immunoglobulin formation in the human neonate
Authors: Andersson Ulf , Bird Graham , Britton Sven
Published: February 2007

The functional capacity of human neonatal B lymphocytes has been investigated by in vitro methods using T lymphocyte‐dependent (pokeweed mitogen, PWM) and‐independent (Epstein‐Barr virus, EBV) polyclonal B cell activators. B cell activation of single cells was detected by class‐specific immunoglobulin (Ig) secretion using a reversed hemolytic plaque assay.

It was found that neonatal B cells were triggered to secretion of IgM by EBV, with a magnitude comparable to adult levels, but that, in contrast to B cells from adults, they did not secrete any IgG. Cord lymphocytes did not secrete Ig although they displayed a sizable DNA synthetic response to PWM. Using cell separation and coculture experiments, it was shown that (allogeneic) adult T lymphocytes could restore cord B cell responsiveness to PWM and that cord T lymphocytes could not cooperate with adult B cells.

In addition to this immaturity of cord T helper function for antibody synthesis, we found cells in the cord T cell‐enriched fraction which inhibited the polyclonal response of adult lymphocytes to both PWM and EBV. These lymphocytes suppressed adult B lymphocytes directly but appeared ineffective against neonatal B lymphocytes themselves. The nature of these suppressing cells and their possible role in the fetal/maternal relationship are a matter of speculation.
Distinct epitopes on Ik gene products identified by monoclonal antibodies
Authors: Pierres Michel , Kourilsky François M. , Rebouah Jean‐Paul , Dosseto Magali , Caillol Danielle
Published: February 2007

Analysis of reactivity of monoclonal anti‐Iak alloantibodies, obtained by fusion between NS 1 myeloma and spleen cells from alloimmune A.TH mice, permitted the identification of 9 distinct determinants of the Ik gene products. Competitive binding experiments indicated that 2 private epitopes (defined by H 8–109.13 and H 8–138.4 antibodies) of the I‐Ak product could be separated, thereby apparently splitting the Ia.2 specificity. A public determinant of the I‐Ak molecule (identified by H 8–15.9 antibody) was found expressed not only on the 1‐A products of the H‐2b, H‐2d, H‐2ja, H‐2P and H‐2q murine haplotypes, but also on human HLA‐DR antigens. Four determinants of the I‐E/Ck antigen (defined by H 7–8.26, H 10–81.10, H 10–93.2 and H 8–86.2 antibodies) had a strain distribution analogous to the Ia.7 specificity. However, competitive binding experiments, and the cross‐reactivity pattern with la‐like antigens from other species (e.g. human HLA‐DR antigens) indicated that these antibodies detected distinct determinants on the I‐E/Ck molecule, thereby subdividing the broad Ia.7 specificity. Two other determinants (defined by H9–14.8 and H9–15.4 antibodies) had a strain distribution that did not permit a precise assignment to a given Ia antigen, even though preliminary data suggested that they could detect separate determinants on the I‐E/Ck product. All these monoclonal antibodies identified membrane antigens with the expected Ia tissue distribution pattern, and most of them could precipitate a molecule containing two chains of 28 kD and 35 kD, from mouse spleen cell lysates.
The rapid isolation of clonable antigen‐specific T lymphocyte lines capable of mediating autoimmune encephalomyelitis
Authors: Ben‐Nun Avraham , Wekerle Hartmut , Cohen Irun R.
Published: February 2007

The isolation and propagation of functional antigen‐specific lines of T lymphoblasts is described. These lines were found to recognize foreign or self antigens in association with accessory cells of syngeneic major histocompatibility complex genotype. Intravenous inoculation of a T cell reactive only against myelin basic protein led to development of clinical paralysis in syngeneic rats. Thus, it is possible to study biological function as well as antigen specificity using T cell lines.
Immunofluorescence studies on the expression of VHa allotypes by pre‐B and B cells of homozygous and heterozygous rabbits
Authors: Gathings William E. , Mage Rose G. , Cooper Max D. , Lawton Alexander R. , Young‐Cooper Glendowlyn O.
Published: February 2007

Fluorochrome‐conjugated antibodies specific for Cμ determinants and VH a allotypes were used to examine pre‐B cells and B lymphocytes for expression of these markers. The majority of μ+ bone marrow pre‐B cells were shown to express a allotypic determinants in conjunction with Cμ. Both pre‐B and B cells from a2a3 heterozygous rabbits showed allelic exclusion of these allotypes. Pre‐B cells expressing the a2 or a3 specificities appeared to be generated in approximately equal numbers in heterozygotes, while B lymphocytes expressing a3 appeared to undergo preferential clonal expansion very early in development. It was also observed that rabbit bone marrow and blood contained a population of myeloid cells which, in a2a3 heterozygotes, stained for both a2 and a3 determinants. The frequencies of this cell type, which exhibited bright immunofluorescence staining for a allotypes, could not be reduced by prolonged incubation at 37°C but were readily reduced after cell suspensions were treated with low pH buffer. It is concluded that these myeloid cells bear high avidity Fc receptors for serum immunoglobulin and may be the culprits in studies which have found production of two a or b allotypes by individual B lymphocytes.
Genetic control of autoimmune encephalomyelitis and recognition of the critical nonapeptide moiety of myelin basic protein in guinea pigs are exerted through interaction of lymphocytes and macrophages
Authors: Ben‐Nun Avraham , Otmy Hanoch , Cohen Irun R.
Published: February 2007

Genetic control has been studied of the response to the encephalitogenic nonapeptide (NP) determinant of myelin basic protein (BP) in inbred guinea pigs of strains resistant or susceptible to induction of experimental autoimmune encephalomyelitis (EAE). By studying bone marrow‐reconstituted animals, we found that susceptibility to induction of EAE was a function of the genotype of the cells of the lymphohematopoietic system and not of the physiological environment or target organ. Analysis of the T cell response showed that susceptible strain 13 or (2 × 13)F1 hybrid guinea pigs recognized the NP determinant when injected with whole BP in adjuvant. Resistant strain 2 guinea pigs responded to undefined determinants on BP, but not to the NP moiety. We investigated the cells involved in regulating the response to the NP determinant by injecting susceptible F1 hybrids with BP‐pulsed macrophages of either parental strain. Susceptible strain 13 macrophages triggered a response to the NP determinant and induced clinical EAE. In contrast, F1 animals injected with resistant strain 2 macrophages failed to respond to the NP determinant, although the macrophages were capable of presenting other undefined determinants present on whole BP. Therefore, genetic control of the immune response to the NP determinant appears to be exerted at the level of antigen presentation by macrophages to T lymphocytes.
Distinctive functional characteristics of human „T”︁ lymphocytes defined by E rosetting or a monoclonal anti‐T cell antibody
Authors: Beverley Peter C. L. , Callard Robin E.
Published: February 2007

The properties of human lymphocyte fractions isolated either by sheep red cell (E) rosetting or by fluorescence‐activated cell sorting after staining with UCHT1 monoclonal anti‐T cell antibody have been compared. Two populations of E+ cells with very different phenotype and function have been identified. E+/UCHT1+ cells respond well to the T cell mitogens phytohemagglutinin and concanavalin A and provide help for an in vitro specific antibody response. They can also suppress the antibody response of allogeneic peripheral blood mononuclear cells. In contrast, the E+/UCHT1− population, which has no other markers characteristic of T cells, fails to respond to mitogens or to provide help or suppression for an antibody response. These cells, however, are highly active natural killers. They possess Fcγ receptors and have a characteristic staining pattern of nonspecific esterase enzyme activity.
Membrane immunoglobulins of spontaneous B lymphomas of aged BALB/c mice
Authors: Laskov Reuven , Kim Jin K. , Woods Virgil L. , McKeever Paul E. , Asofsky Richard
Published: February 2007

Four cell lines derived from spontaneous BALB/c B lymphoma tumors were analyzed with regared to the type of their membrane immunoglobulins (Ig). Using lactoperoxidase iodination of membrane proteins combined with immunoprecipitation and electrophoresis on polyacrylamide gel, three of these cell lines (X16c, L10A and K46) were found to express the monomeric form of IgM and IgD as well as half molecules. One cell line (M12) lacked both IgM and IgD. The apparent mol. wt. of the lymphoma μ chain was about 80000 and exceeded the mol. wt. of 75 000 determined for μ chains secreted by myeloma cells. The mol. wt. of the δ heavy chain was found to be 66000. Immunofluorescence showed that the L10A and X16c lines expressed λ light chains on their cell surface. Another Ig‐bearing cell line (K46) expressed both λ and χ chains. Thus, three out of the four B lymphomas examined expressed both IgM and IgD with light chains of the δ type. These results, together with our previous findings which demonstrate the presence of Ia and Fc receptors on the same cells, indicate that spontaneous B lymphomas in BALB/c mice are the malignant counterpart of mature B lymphocytes.
Activation of T lymphocytes by lectins and carbohydrate‐oxidizing reagents viewed as an immunological recognition of cell‐surface modifications seen in the context of “self” major histocompatibility complex antigens
Authors: Kimura Arthur , Ersson Bo
Published: February 2007

The experiments reported here were directed at the question of whether polyclonal activation of T cells by mitogenic substances results as a consequence of (a) a truly antigen‐independent stimulation of T cells through mitogen receptors, bypassing requirements for T cell‐specific recognition or (b) an immunological reaction, similar in principle and requirements to T cell activation induced by antigen. Several lines of evidence have provided strong support for the latter interpretation. First, the ability of several mitogenic substances to induce polyclonal T cell activation was found to be crucially dependent upon cell surface expression of major histocompatibility complex (MHC) products. Thus, the presence of alloantisera or monoclonal antibodies directed against either class I (SD) determinants or class II (Ia) products on the responding cell population resulted in a sizeable dose‐dependent inhibition of the mitogenic response. Additional studies using spleen cells from normal F1 mice or F1→parent bone marrow chimeras provided the most direct and convincing evidence for a specific immunological role of MHC products in mitogenic T cell activation. Here, the concanavalin A response of normal F1 T cells was found to be inhibited by alloantisera against either parental haplotype, while the H‐2‐heterozygous F1→parent chimeras were only inhibited by antisera against the H‐2 of the parent in which they matured and possessed functional, MHC‐restricted helper T cells.

The inherent characteristics and reactivities which endow only certain lectins to exert a mitogenic effect were specifically examined in light of the observed dependence for MHC expression in these mitogenic reactions. Using a panel of 20 different lectins as affinity absorbents for cell surface glycoproteins, it was found that only mitogenic lectins were capable of binding to cell surface‐expressed H‐2 products (both K/D and la). The results obtained here are discussed in support of the concept that mitogeninduced T cell responses involve an immunological recognition of cell surface modifications seen in the context of self H‐2 antigens.
Cytotoxic T cell recognition of Epstein‐Barr virus‐infected B cells. I. Specificity and HLA restriction of effector cells reactivated in vitro
Authors: Moss Denis J. , Wallace Lesley E. , Rickinson Alan B. , Epstein M. Anthony
Published: February 2007

The experiments show that the phenomenon of regression, seen exclusively in Epstein‐Barr (EB) virus‐infected cultures of mononuclear cells from EB virus antibody‐positive donors, is mediated by cytotoxic T cells reactivated in vitro and specifically recognizing an EB virus‐induced lymphocyte‐detected membrane antigen LYDMA. Thus, effector T cells from regressing cultures kill autologous EB virus‐transformed cells but not autologous pokeweed mitogen‐stimulated lymphoblasts nor any of a range of EB virus genome‐negative human hemopoietic cell lines (K562, HSB2, BJAB, EB4) particularly sensitive to nonspecific natural killer‐like activities. Moreover, these reactivated effector cells exhibit classical HLA restriction of target cell recognition; in a survey of 14 effector cell donors, preferential lysis of the autologous virus‐transformed line was a consistent feature, while the relative degree of lysis of allogeneic lines was in general directly related to the number of HLA‐A and B antigens shared between effector and target cells. The pattern of reactivity shown by effector T cell preparations from any one donor was strikingly reproducible, and the results from a number of donors revealed differences between particular HLA‐A and B antigens with respect to the level of EB virus‐specific killing which was associated with sharing through these determinants.
Suppression of lymphocyte reactivity in vitro by a soluble factor secreted by explants of human decidua
Authors: Golander Avraham , Zakuth Vera , Shechter Yoram , Spirer Zvi
Published: February 2007

The immunologic mechanisms that protect the fetus from rejection were the subject of numerous investigations. Reports showing the uterus as a favorable site of implantation focused our attention to the decidua which is the maternal tissue intimately attached to fetal structures.

Explants of human decidua were cultured for periods of 24 h and incubation media tested for their immunosuppressive activity. The incubation medium of human decidua when added to cultures of human lymphocytes suppressed both their reactivity to lectins and their activity in the mixed lymphocyte reaction. The results of these experiments suggest that decidual tissue releases a soluble factor which is a potent inhibitor of cell‐mediated immunity.
I region‐restricted T cell line stimulated with haptentreated syngeneic cells: Selection of clones with reactivity for both allogeneic Ia determinants and self‐I‐A plus hapten
Authors: Guimezanes Annick , Albert Françoise , Schmitt‐Verhulst Anne‐Marie
Published: February 2007

The apparent switch in proliferative T cell reactivity which occurred in a B10 T cell line (B10(T4)) repeatedly stimulated with trinitrobenzene sulfonic acid (hapten)‐treated syngeneic cells is described. This functionally heterogenous T cell population, apparently depleted of alloreactivity and strictly dependent on cells expressing syngeneic I‐A and the hapten for its propagation, lost, after its 10th restimulation, the previously detected T cell functions, and expressed a new pattern of proliferative reactivity; this pattern included reactivity to self‐I‐A plus hapten as well as to untreated stimulating cells expressing certain allogeneic determinants. Analysis of reactivity of B10(T4) cells grown under limiting dilution conditions and of five clones of cells derived from B10(T4) indicated that the same T cells were reactive to both self‐I‐A plus hapten, and to a public I‐A‐mapped alloantigen possibly related to the serologically defined Ia.5 specificity.
Autoimmune effector cells. II. Transfer of experimental allergic encephalomyelitis with a subset of T lymphocytes
Authors: Holda James H. , Swanborg Robert H.
Published: February 2007

This study was conducted to further characterize the effector cells of experimental allergic encephalomyelitis (EAE) which are activated in vitro when spleen cells from Lewis rats previously immunized with myelin basic protein and adjuvant are cultured with antigen prior to transfer to syngeneic recipients. The effector cells were isolated on discontinuous Percoll gradients in the cell fraction that floated on Percoll with a buoyant density of 1.067 kg/l. These cells (designated fraction 1) transferred EAE and incorporated [3H]dThd in culture. Fraction 1 was enriched for T cells when evaluated with monoclonal anti‐rat T cell serum W3/13 and deficient in Ig+ cells; approximately 33% were positive with monoclonal anti‐rat T cell serum W3/25. In contrast, the small, nonproliferating cells found in higher density Percoll fractions did not transfer EAE.

When fraction 1 was recultured in the presence of basic protein and interleukin 2 for 72 h, these cells retained the ability to transfer EAE. Moreover, these recultured cells exhibited an increase in the W3/25 antigen and a decrease in the W3/13 marker. It was concluded that a subset of T cells which bear the W3/25 marker is involved in the transfer of EAE.
Analysis of Fcγ receptors on human peripheral blood leukocytes by flow microfluorometry. I. Receptor distributions on monocytes, Tγ cells and cells labeled with the 3A1 anti‐T cell monoclonal antibody
Authors: Titus Julie A. , Haynes Barton F. , Thomas Charles A. , Fauci Anthony S. , Segal David M.
Published: February 2007

A dual parameter flow microfluorometric technique for accurately measuring Fcγ receptor (FcR) expression on defined subsets of cells within a heterogeneous cell sample was developed. The FcR distribution of human peripheral blood mononuclear cells consists of three distinct peaks. By analyzing cells fluorescently labeled with the 3A1, an anti‐T cell hybridoma antibody (using a green‐emitting fluorophore) and for FcR (with a red‐emitting fluorophore), and by using cell isolation procedures, it was shown that the cells lying within the peak with intermediate FcR density are mainly monocytes, while cells lying within the peaks with highest and lowest (i.e. negative) FcR densities are predominantly T cells. The FcR+ T cells (Tγ cells) express higher levels of the 3A1 antigen than other T cells, thus demonstrating the utility of the 3A1 hybridoma antibody as a marker for Tγ cells.
Immunoglobulin C‐gene expression. III. Possible induction of specific genetic events in activated B lymphocytes by the polyclonal stimuli driving clonal expansion
Authors: Martinez‐Alonso Carlos , Coutinho Antonio
Published: February 2007

Polyclonal activation of resting B lymphocytes by either lipopolysaccharide or specific helper cells recognizing antigens on B cell membranes results in selective patterns of IgG subclass expression among plaque‐forming cells. We have studied the IgG subclasses of plaque‐forming cells generated in cultures of purified B cell blasts selected for reactivity to either LPS or helper cells, and restimulated by either lipopolysaccharide, specific helper cells, or as “bystanders”, by nonspecific B cell growth factors. Development of IgG1 plaque‐forming cells is observed only when clonal expansion is maintained by specific helper cells, whereas IgG3 secretion specifically requires stimulation by lipopolysaccharide and the absence of helper cell activity. Furthermore, exposure of resting B lymphocytes to specific helper cells induces, in 48 h, an irreversible loss of the potential to produce IgG3. Other than showing that helper cell‐dependent B cell growth and maturation is more complex than previously suspected, these results suggest that differentiation signals or factors induce specific DNA recombination and deletion events.
Immunological focusing by the mouse major histocompatibility complex: Mouse strains confronted with distantly related lysozymes confine their attention to very few epitopes
Authors: Katz Michael E. , Maizels Richard M. , Wicker Linda , Miller Alexander , Sercarz Eli E.
Published: February 2007

The gallinaceous lysozymes are a family of antigens that are distantly related to mouse lysozyme. A T cell‐dependent proliferation assay was used to characterize the spectrum of reactivities to lysozyme determinants in B10‐congenic mice. Cross‐reactivity studies using a panel of species variant lysozymes to stimulate lymph node cells from chicken egg white lysozyme‐ and ring‐necked pheasant egg white lysozyme‐primed B10.D2 mice indicated a preferential focusing of T cell reactivity onto a single determinant containing amino acids 113‐114. These data, in conjunction with results obtained by priming with cyanogen bromide cleavage fragments of lysozymes, suggested that a site common to the L3 region (amino acids 106‐129) of all the lysozymes tested was a preferential anchorage site for I region‐encoded la molecules on H‐2d antigen‐presenting cells, leading to the limited display of a determinant containing residues 113‐114.

Priming with L2H (amino acids 13‐105), a peptide containing the major epitopes recognized by B10.A and B10 mice, failed to stimulate any T cell proliferation by B10.D2 lymph node cells. Thus, it appears the la molecules in any one mouse strain attach to very few sites on lysozyme to effectively display antigenic determinants for T cell activation. This result points to a model of limited determinant selection even on a very “foreign” antigen based upon a shortage of appropriate amino acid residues usable by la antigen‐presenting structures of a strain.
Human cytotoxic T cell structures associated with expression of cytolysis. I. Analysis at the clonal cell level of the cytolysis‐inhibiting effect of 7 monoclonal antibodies
Authors: Malissen Bernard , Rebai Najet , Liabeuf André , Mawas Claude
Published: February 2007

Monoclonal antibodies (mAb) derived from BALB/c mice immunized with human anti‐HLA‐A2 cloned cytotoxic T lymphocytes (CTL) were screened for their ability to block, in the absence of complement, the cytolytic activity of the immunizing CTL clone. Eight cytolysis‐inhibiting mAb have been derived. One of these was directed against a monomorphic determinant expressed on HLA‐class I molecules and thus probably inhibited cytolysis via a target cell antigen‐masking effect. The 7 other mAb recognized “CTL function‐associated structures” and did not have to interfere with target cell antigens in order to inhibit cytolysis. F(ab')2 and Fab fragments of these 7 mAb were also inhibitory. Competitive inhibition of binding and preliminary biochemical analysis suggested that these 7 mAb defined on cloned CTL various epitopes of a structure of 30 kDa disulfide‐bonded into several multimeric forms when analyzed without reduction. The inhibitory effect of these 7 mAb has been investigated on a series of short‐term (1 month) and long‐term (> 10 months) expanded cloned CTL lines derived in vitro from an in vivo allosensitized individual exhibiting various specificities. Unexpectedly, only 10% of these CTL clones were inhibited. Flow cytofluorimetric analysis further revealed that noninhibited and inhibited CTL clones expressed similar amounts of the 30‐kDa structure. Consequently, the inhibition of CTL was heterogeneous when analyzed at the clonal level and not simply related to the presence or absence of this structure. Furthermore, the ability of CTL clones to be inhibited appeared to be unrelated to their HLA‐A, B or C specificity or to their lytic activity. The connections between this mAb‐defined structure and CTL function are discussed.
Suppression of cell‐mediated lymphocytotoxicity against minor histocompatibility antigens mediated by Lyt‐1+Lyt−2+ T cells of stimulator‐strain origin
Authors: Rammensee Hans‐Georg , Nagy Zoltan A. , Klein Jan
Published: February 2007

Cultured, unprimed spleen cells suppress the generation of cytolytic T lymphocytes when added to mixed lymphocyte culture of cells disparate at minor histocompatibility (H) loci. Cells cultured for 2 to 3 days inhibit cell‐mediated lympholysis specifically in that they suppress only when they carry the same H antigen by which the stimulators activate the responding cells. However, culturing of cells for more than 3 days results also in the generation of nonspecific suppressor cells which inhibit the cell‐mediated lympholysis regardless whether they carry the stimulating antigens. The specific suppressor cells are T lymphocytes of the Lyt‐l+Lyt−2+ type. Fresh, uncultured spleen cells, although ineffective in vitro, can prevent the in vivo priming of minor H‐specific cytotoxic T lymphocyte precursors when injected i.v. into mice incompatible at minor H loci. This suppressive effect of the immunizing inoculum is abolished by irradiation (3300 rds) or by treatment with a monoclonal Thy‐1‐specific antibody and complement. Thus the suppressor T cell demonstrated here is of the “veto” cell type; that is, it probably suppresses minor H‐specific cells when the latter recognize the stimulating antigen on the surface of the suppressor cell itself.
Tissue distribution and ontogenetic emergence of differentiation antigens on avian T cells
Authors: Peault Bruno , Coltey Monique , Douarin Nicole M. Le
Published: February 2007

Two distinct antibodies raised against quail thymocytes were used in an indirect immunofluorescence assay to analyze the expression of differentiation antigens on T lineage cells in embryonic and newly hatched quail, (a) A rabbit serum, anti‐AT‐65, that has been previously shown to immunoprecipitate a protein of apparently 65‐70 kDa from quail and chick thymocytes, reacts with both thymic and peripheral T cells. The polyspecificity of this pan‐avian T cell reagent can be dissected by absorption and includes reactivities against two distinct antigenic entities. One of these is restricted to thymocytes whereas the other is also expressed on peripheral T cells, (b) A monoclonal antibody, a‐TD1, defines the population of cortical thymocytes and does not react with peripheral T cells. Binding assays during the embryonic development of the T lineage reveal that specific surface markers are expressed 36 h following the seeding of lymphoid precursor cells to the thymic rudiment, suggesting their early commitment in this lymphoid microenvironment. T cells are also shown to be exported precociously to the embryonic splenic compartment.
The distribution, ontogeny and origin in the rat of Ia‐positive cells with dendritic morphology and of Ia antigen in epithelia, with special reference to the intestine
Authors: Mayrhofer Graham , Pugh Christopher W. , Barclay A. Neil
Published: February 2007

Ia antigens were localized in cryostat sections of rat intestine and other tissues by an indirect immunoperoxidase technique using monoclonal antibodies that recognize the rat antigens homologous to the gene products of the I‐A and I‐E subregions of the mouse major histocompatibility complex (MHC). Two categories of Ia+ cells were characterized, namely epithelial cells and bone marrow‐derived cells with dendritic morphology. In the small intestine Ia antigen was present in the distal 2/3 of the absorptive epithelium but absent from the bases of the villi, the crypts and the epithelium covering the Peyer's patches. The distribution in nude rats was similar, indicating that T lymphocytes are not obligatory for its expression. In ontogeny Ia antigen was absent in the epithelium of neonatal gut, appearing at about 4 weeks of age and reaching adult levels at about 6 weeks. Different rat strains showed large differences in the amount of Ia antigen expressed by villus epithelium and the traits for the level of expression were shown to map outside the MHC. The levels of expression of Ia antigen in the proximal tubules of the kidney followed that of the gut epithelium in the different strains and in both tissues was mostly intracellular. Studies with chimeras showed that the Ia antigen in epithelial cells was not acquired from bone marrow‐derived cells.

The second category of cell studied had a characteristic dendritic morphology and was present in large numbers in the lamina propria of the villi and in the crypts. In the Peyer's patches these cells were present both in the subepithelial dome region and within the epithelium itself. These Ia+ dendritic cells were present in nude rat jejunum and appeared in normal fetal gut by 18 days gestation and were also shown to migrate into antigen‐free grafts of fetal gut. This suggests that they do not require stimulation from antigens, bacterial products or T lymphocytes in order to localize in the gut or to express Ia antigen. Studies with other cell surface markers suggest that the Ia+ cells with dendritic morphology represent a range of cell types, some with similarities to macrophages and others to nonphagocytic dendritic cells.
Distinct helper activities control growth or maturation of B lymphocytes
Authors: Pettersson Sven , Pobor Grgur , Bandeira Antonio , Coutinho Antonio
Published: February 2007

A clone (C‐11) of C3H/HeJ Lyt‐1+2− T cells with specificity for “minor” antigens of C3H/Tif has been isolated which, in contrast to other similarly derived clones, did not activate polyclonal plaque‐forming cell (PFC) responses in T cell‐depleted “target” spleen cells. This clone, however, showed unaltered proliferative responses to the naturally occurring antigen(s) on presenting cells, and strongly synergized with regular helper clones in the induction of PFC responses. Further analysis demonstrated that C‐11 cells are competent to stimulate extensive “target” B cell proliferation, but lack the ability to produce (or participate in the production of) maturation factors for activated B cells. Thus, the defective PFC responses could be fully reconstituted with supernatants from regular clones stimulated with antigen, but not by supernatants prepared from the C‐11 cells themselves.

While it is not clear whether this clone represents a normal helper T cell subpopulation or a variant that has lost maturation‐factor production, these results demonstrate that distinct factors control growth and maturation in T cell‐dependent B lymphocyte responses.
Normal human B cells express endogenous sheep erythrocyte (E) receptor after appropriate in vitro culture
Authors: Mills Kingston H. G. , Worman Colin P. , Cawley John C.
Published: February 2007

When normal human B cells from blood, tonsil or spleen are cultured with 20–30% autologous or allogeneic T cells and mitogen, the majority of cells rosette with sheep erythrocytes (E) after 3–5 days in culture. These E+ cells are of transformed appearance and several points indicate that many are derived from B cells. Some simultaneously possess surface immunoglobulin (sIg) or a B cell antigen [detected with BA1 monoclonal antibody (mAb)] and E receptor. Many do not stain with anti‐T cell mAb (UCHT1, OKT4, OKT8), while cultured T cells continue to express these antigens. Furthermore, many E+ cells appear when the original T cells have been irradiated. All the cultured E+ cells stain with OKT11, an mAb against the E receptor, and their positivity cannot therefore be attributed to mitogen‐induced nonspecific stickiness. The E positivity of the B cells was shown to be endogenous since passive acquisition of E receptor shed by T cells was excluded in a number of ways; no phenotypic changes were observed when supernatants from cultures containing many E+ sIg+ non‐T cells were added to B cells, or when the B and T cells were separated by a Millipore membrane; and E receptor was re‐expressed after stripping with trypsin or pronase. The intimate presence of T cells is essential for the expression of E receptors by B cells, and this helper capacity was shown to reside within the OKT4‐defined helper T cell subpopulation. The significance of the expression of E receptor by B cells is discussed in relation to the recent in vitro and in vivo demonstration of E+ sIg+ cells in certain leukemias and in relation to the specificity of E rosetting as a marker of T cells.
In vitro propagation of cultured human natural killer cells expressing the HNK‐1 differentiation antigen and spontaneous cytotoxic function
Authors: Abo Toru , Balch Charles M.
Published: February 2007

Human natural killer (NK) cells expressing the HNK‐1 differentiation antigen were established in long‐term tissue culture for over 3 months. The fluorescence‐activated cell sorter‐purified HNK‐1+ cells required both phytohemagglutinin and exogenous interleukin 2 to propagate in long‐term culture. After 2 weeks of culture, virtually all of the growing cells exhibited the surface membrane phenotype associated with immature HNK‐1+ cells, since they simultaneously expressed the HNK‐1, Leu‐4 and Leu‐2a but lacked the M1, Leu‐3a and T6 antigens, and Fcγ receptors. They exhibited a lymphoblastoid appearance, contained cytoplasmic granules, and exhibited spontaneous cytotoxic function against a broader spectrum of target cells than did fresh HNK‐1+ cells from the same donor. Cultured HNK‐1+ cells lacked antibody‐dependent cell‐mediated cytotoxic (ADCC) function, while fresh HNK‐1+ were fully capable of ADCC function. On the other hand, cultured HNK‐1− cells were lymphoblasts without cytoplasmic granules or NK cytotoxic function. The cultured HNK‐1+ cells gradually lost their HNK‐1 antigen expression over time, although the expression of other surface antigens (e.g., Leu‐4 and Leu‐2a) was unchanged. With prolonged culture (> 2 months), they also exhibited decreasing cytotoxic function and a diminished number of cytoplasmic granules. They were eventually indistinguishable from HNK‐1− cells after 3 months of culture. These observations were not influenced by adding interferon‐γ to the cultures. The results demonstrate that the immature form of NK cells (that express T cell antigens) preferentially proliferate in long‐term cultures when incubated with phytohemagglutinin and interleukin 2.
In vitro correction of the interleukin 2 defect of autoimmune mice
Authors: Santoro Thomas J. , Luger Thomas A. , Ravache Elizabeth S. , Smolen Josef S. , Oppenheim Joost J. , Steinberg Alfred D.
Published: February 2007

The effect of concanavalin A (Con A) and/or phorbol myristate acetate (PMA) on interleukin 2 (IL2) production and tritiated thymidine incorporation was measured in young (6 weeks) and old (16‐24 weeks) autoimmune mice by pulsing 5 × 106 unfractionated spleen cells with 5 μg of Con A and/or 5 ng of PMA for variable periods of time. The apparent deficiency in Con A‐stimulated IL2 production manifested by mice prone to the development of autoimmune disease was repaired by the addition of PMA. PMA did not enhance interleukin 1 (IL 1) secretion in autoimmune MRL‐lpr mice either alone or in combination with Con A. The addition of purified IL 1 to Con A‐pulsed autoimmune cells did not increase IL2 production. Freeze‐thaw experiments suggested that PMA does not promote IL2 synthesis. Con A‐pulsed cells plus PMA‐pulsed cells do not syngergize. These data indicate that autoimmune‐prone mice are capable of producing IL 2 and of proliferating in response to Con A provided the comitogen PMA is present. It can be argued that the failure to produce IL2 or to respond to proliferative signals is not fundamental to the development of the disease sustained by autoimmune‐prone mice.
Haplotype‐specific suppressor T cells mediating linked suppression of immune responses elicited by third‐party H‐2 alloantigens
Authors: Holáň Vladimír , Mitchison N. Avrion
Published: February 2007

Specific suppressor T cells (Ts) were induced in vitro by incubation of mouse spleen/lymph node cells with allogeneic heat‐treated cells. These Ts inhibit mixed lymphocyte reaction (MLR) in a haplotype‐specific manner. Ts also suppress cell proliferation induced by third‐party H‐2 alloantigens provided these are expressed on the same cell surface as at least some of the H‐2 antigens used for Ts activation. Ts activated by H‐2 plus non‐H‐2 alloantigens suppress an MLR induced by irrelevant H‐2 alloantigens if these are expressed on the same cell surface as the non‐H‐2 alloantigens used for Ts activation. Products of the H‐2 region or non‐H‐2 alloantigens which are not able to stimulate cell proliferation do not activate Ts. These Ts are first demonstrable after 4 days of incubation of lymphoid cells with heat‐treated allogeneic cells and they inhibit MLR only if added at the very beginning of the culture. Exogenous interleukin 2 does not overcome suppression and the suppression is not due to a cytotoxic effect, since heat‐treated cells do not elicit cell proliferation or cytotoxic cells. Moreover, the specific Ts differ in their Thy‐1+,Ly‐1+,2− phenotype from Ly‐2+ allospecific cytotoxic cells. Thus specific Ts could be induced in vitro, which demonstrate linked suppression for third‐party H‐2 alloantigens provided these are expressed on the same cell surface as the antigens used for Ts activation.
Accessory functions and mutual cooperation of murine macrophages and dendritic cells
Authors: Miyazaki Hiroshi , Osawa Toshiaki
Published: February 2007

In this study the antigen‐presenting functions of murine splenic dendritic cells (DC) and macrophages (MΦ) have been compared. DC and MΦ were pulsed with keyhole limpet hemocyanin (KLH) and found to contain approximately 92% and 50% Ia‐positive cells, respectively. The two KLH‐pulsed cell populations had almost equal ability to stimulate KLH‐immune T cells. The antigen‐presenting functions of DC and MΦ were compared by measuring the capacity of KLH‐pulsed, UV‐irradiated cells, which failed to secrete interleukin 1 (IL1), to stimulate KLH‐immune T cells when each culture was supplemented with an equal amount of exogenous IL1. The antigen‐presenting capacity of DC was always greater than that of MΦ. Coculturing of the two kinds of accessory cells upon KLH pulsing resulted in enhanced antigen‐presenting capacity of the mixture relative to the same number of each accessory cell type. That is, collaboration between them in antigen presentation was clearly observed. However, direct contact between DC and MΦ was not obligatory for this collaboration. Furthermore, we found that different types of soluble factors released by each of them might be responsible for the collaboration. In addition, supernatants of concanavalin A‐stimulated spleen cells augmented the antigen‐presenting function of only MΦ. Finally, the antigen‐presenting function of DC and MΦ from athymic mice was almost the same as that from control mice.
Heterogeneous and monoclonal helper T cells induce similar anti‐(4‐hydroxy‐3‐nitrophenyl)acetyl (NP) antibody populations in the primary adoptive response II. Lambda light chain dominance and idiotope expression
Authors: Smith Frances I. , Tesch Hans , Rajewsky Klaus
Published: February 2007

When the hapten (4‐hydroxy‐3‐nitrophenyl)acetyl (NP) is presented on different carrier molecules, different anti‐NP antibody responses are stimulated. On stimulation with NP‐lipopolysaccharide (LPS) [T‐independent type 1 (TI‐1) antigen] kappa (x)+ antibodies are the major population, whereas on stimulation with NP‐Ficoll [T‐independent type 2 (TI‐2) antigen], NP‐keyhole limpet hemocyanin (KLH) or NP‐chicken gamma globulin (CG) [T‐dependent (TD) antigens], lambda (λ) 1+ antibodies dominate. The relative contribution of idiotopes Ac38 or Ac146 to the λ1+ anti‐NP response was also different on comparison of TI‐1 with TI‐2 or TD anti‐NP responses. We investigated whether light chain‐ or idiotype‐specific T cells are responsible for these differences. Analysis of the anti‐NP response of nude mice after immunization with NP‐Ficoll showed λ1 dominance. Likewise primary adoptive transfer experiments using carrier‐specific T cell lines to reconstitute the TD anti‐NP response to NP‐KLH or NP‐CG, showed that help from carrier‐specific T cells alone is capable of stimulating the characteristic λ1 dominant response. No significant difference could be found in the levels of Ac38 and Ac146 idiotope expression between mice reconstituted with splenic T cells and those reconstituted with T cell lines. These results suggest that light chain‐ or idiotype‐specific T cells are required neither for the production of λ1 light chain dominance, nor for the appearance of idiotopes characteristic of the primary anti‐NP response. The possible reasons for differences seen in both light chain and idiotope expression between primary anti‐NP responses to the TI‐1 antigen NP‐LPS and those to TD or TI‐2 antigens are discussed.