bluuebunny/crossref_metadata_2025 huggingface dataset:
Isotype commitment in the in vivo immune responses. II. Polyclonal plaque‐forming cell responses to lipopolysaccharide in the spleen and bone marrow
Authors: Björklund Mariana , Coutinho Antonio
Published: February 2007

Injection of lipopolysaccharide into adult mice results in a rapid increase in the number of splenic IgM‐secreting plaque‐forming cells (PFC) so that by 60 h they represent roughly 20 times those present in normal mice. Although inhibited for the first two days, IgG3, IgG2b and IgG2a PFC are later selectively stimulated and, by 110 h, they reach numbers that are 100, 40 and 30 times, respectively, those of normal mice. IgG1 PFC are stimulated only marginally and 48 h after the maximal responses of the other IgG subclasses. IgA PFC are selectively inhibited and drop to 20% of normal numbers 4 days after injection. The ability of lipopolysaccharide to selectively stimulate B cells for the production of IgG3, IgG2b and IgG2a was further substantiated by studying athymic mice, and by using adoptive cell transfers that overcome regulatory influences limiting these responses in intact mice. Under these conditions, 16% of all spleen cells are PFC and up to 85% of all Ig‐secreting cells are included in those three isotypes. Similar responses are also detected in bone marrow but they occur 24–48 h after the splenic responses, suggesting that bone marrow PFC are not induced in situ. These results demonstrate a selective in vivo isotype commitment in response to lipopolysaccharide that is polyclonal and, therefore, independent of V region specificities.
Splenic B cells function as immunogenic antigenpresenting cells for the induction of effector T cells
Authors: Tzehoval Esther , De Baetselier Patrick , Ron Yacov , Tartakovsky Boris , Feldman Michael , Segal Shraga
Published: February 2007

Previous studies performed in our laboratory have revealed that an ordered, sequential, tricellular interaction is obligatory for the antigen‐driven induction of a specific effector memory T cell. Thus, it was found that antigen‐pulsed peritoneal macrophages signal, in spleen cells, the generation of antigen‐specific initiator lymphocytes. These lymphocytes, following injection to syngeneic recipients, recruit, in the draining lymph nodes, “virgin” antigen‐reactive T lymphocytes. Although the nature of the first and last cell in the interacting sequence was well characterized, the identity of the intermediary initiator splenic cell was obscure. Studies were carried out to characterize the nature of the splenic initiator cells. It was found that spleen cells from nu/nu, adult thymectomized and neonatal thymectomized, or spleen cells from normal donors which had been subjected to cytolysis using anti‐Thy‐1.2 antibodies in the presence of complement, did generate, following interaction with keyhole limpet hemocyanin (KLH)‐fed macrophages, specific initiator cells. Carrageenan impairment of spleen macrophages did not affect the generation of initiator cells, nor did the depletion of dendritic cells from the spleen. On the other hand highly enriched B cell, but not highly enriched T cell populations, when seeded on KLH‐pulsed macrophages, generated antigen‐specific initiators, which, in vivo, recruited antigen‐reactive T cells. It thus appeared that B lymphocytes can function as intermediary obligatory antigen‐presenting cells and actively transfer immunogenic signals from peritoneal antigen‐presenting cells to T lymphocytes. These findings may therefore suggest that antigen‐specific B cells do not function solely as antibody‐producing cells, but, once activated by macrophages, may control the induction and differentiation of some antigen‐reactive T cell subsets. Thus, one can view the B cell as an important regulatory cell of both cellular and humoral immune functions. The significance of this observation with regard to Ir gene control at the level of B lymphocytes is discussed.
The preparation of mouse VH fragments and the characterization of heterologous anti‐mouse VH antibodies
Authors: Karjalainen Klaus
Published: February 2007

VH fragments were prepared from several mouse IgM molecules by cyanylation. In all cases VH fragments were purified to homogeneity by using Ig light chain affinity columns. Several different anti‐VH antisera were prepared in rabbits and the specificities of these antibodies were studied. Two patterns of cross‐reactivities were observed: (a) some anti‐VH antibodies reacted only with closely related VH molecules, e.g., anti‐VH HPC52 anti bodies reacted only with VH of phosphorylcholine‐binding myeloma or hybridoma protesin, and concrodantly, stained about 4% of mouse spleen B cells; (b) on the other hand, antisera‐like anti‐VH 104E and 8916 antibodies were very cross‐reactive. Binding assays showed that both of these anti‐VH antibodies reacted with 50–60% of mouse immunoglobulins, and thus the pool of these antibodies reacted with about 95% of mouse VH regions. Concordantly, anti‐VH 104E antibodies stained in the fluorescence‐activated cell sorter (FACS) analysis more than 50% of mouse spleen B cells.

Cross‐reactive anti‐VH antibodies (“anti‐framework”) did not stain T cells nor did they immunoprecipitate VH‐like molecules which were synthesized by T cells.
Electron microscopy of the complement protein C1q from the bullfrog, Rana catesbeiana
Authors: Slayter Henry S. , Alexander Richard J. , Steiner Lisa A.
Published: February 2007

The complement protein C1q, isolated from bullfrog (Rana catesbeiana) serum, was found by electron microscopy to resemble human C1q; peripheral globular units, probably six in number, are connected by thin strands to a hollow stem‐like central structure. The dimensions of frog and human C1q were also found to be very similar. These results are consistent with earlier observations that frog and human C1q are similar, although not identical, in overall size, subunit structure, amino acid composition, and functional properties. Evidently this protein, which binds to antigen‐antibody complexes and to C1r and C1s, thereby forming a physical link between the immune and complement systems, has been highly conserved in evolution.
The genetic basis of antibody production: A single heavy chain variable region gene encodes all molecules bearing the dominant anti‐arsonate idiotype in the strain A mouse
Authors: Siekevitz Miriam , Huang Shu Ying , Gefter Malcolm L.
Published: February 2007

A nucleic acid probe specific for heavy chains bearing the cross‐reactive idiotype (Id) associated with the anti‐p‐azophenylarsonate response of strain A mice has been prepared. Analysis of arsonate‐binding Id+ hybridoma cell lines has revealed that all of them contain the same germ‐line VH gene rearranged to the JH2 segment. An Id+ hybridoma which is unable to bind arsonate utilized the same VH gene, but it has apparently rearranged to the JH4 segment. Id− cell lines contain other rearranged VH genes. Analysis of DNA of strain A mice revealed that there is apparently only one germ line gene that can give rise to Id+ heavy chains. Since the Id is expressed as a large collection (> 50) of related but nonidentical heavy chain sequences, we conclude that their diversity is the result of a somatic mutation process. Analysis of a single hybridoma cell line (45–59) reveals that somatic mutation can operate on an Id‐encoding gene and result in an antigen‐binding molecule that has lost all of its Id determinants. Further analysis of the genome of strain A mice has revealed the presence of germ‐line genes differing from the Id‐encoding gene by at least 8 base pairs. These genes, however, apparently do not contribute to the anti‐arsonate Id response.
Temperature and cellular regulation of spontaneous cytotoxicity in the shark
Authors: Pettey Carolyn L. , McKinney E. Churchill
Published: February 2007

Spontaneous cytolytic activity of shark peripheral blood leukocytes is observed only during periods of decreased environmental temperature (< 23°C). The effector cell is adherent to glass and is phagocytic. Leukocytes tested during warmer periods (26–31°C) exhibit no spontaneous activity; however, glass‐adherent cells isolated from those fish are cytotoxic in vitro, indicating that the effector cell is present at all temperatures. During warmer temperatures, nonadherent cells added to adherent cells were shown to inhibit spontaneous cytotoxicity. This inhibition requires viable cells in contact with the spontaneous cytotoxic population. Thus decreased environmental temperature correlated with spontaneous cytotoxicity, and appears to affect a regulatory cell that is glass nonadherent. In addition, the cytotoxic effector cell is more active at 23°C than 30°C in vitro. These data show that by the time of emergence of the nurse shark, a temperature‐dependent mechanism had evolved for cellular regulation of at least one immune function, spontaneous cytotoxicity.
Regulation of plasminogen activator secretion, interferon induction and proliferation in murine macrophages
Authors: Neumann Christine , Sorg Clemens
Published: February 2007

The purpose of this work was to study the interrelationship of proliferation and secretion of plasminogen activator (PA) and interferon (IFN) by murine macrophages. For induction of macrophage proliferation and secretion of PA, concanavalin A (Con A) was used. Secretion of IFN was induced by polyinosinic polycytidylic acid complex. The glucocorticoid dexamethasone acetate (DA) (10−6 − 109 M) inhibited Con A‐stimulated secretion of PA and synthesis of DNA as evaluated by incorporation of [3H]thymidine. DA did not inhibit IFN induction. Preincubating macrophages with DA for 45 h reduced basal proliferation and secretion of PA but did not reduce responsiveness to Con A. Also retinoic acid, a modulator of carcinogenesis was used in inhibition studies because of its known antagonistic effects on lymphocyte mitogenesis. In macrophages a biphasic effect of retinoic acid (1 × 10−5 − 5 × 10−5M) was found: (a) inhibition of DNA synthesis and secretion of PA during the first 45 h of incubation, and (b) enhancement of DNA synthesis (but not PA secretion) after 72 h. Secretion of IFN was not affected. It is suggested that secretion of PA but not IFN is linked to cell cycle traverse of macrophages.
A monoclonal anti‐HLA antibody recognizes a mouse tumor‐associated antigen
Authors: Evan Gerard I. , Lennox Edwin S. , Alderson Thomas , Croft Lorraine
Published: February 2007

The monoclonal antibody W6/32.1 recognizes a public determinant on the HLA‐A, B and C antigens of all tested human haplotypes. Though the antibody does not bind to normal mouse cells of any H‐2 haplotype, it does show an unexpected specificity for the T cell leukemia line MBL‐2 from a C57BL/6 mouse. It is shown that the murine antigen recognized by W6/32.1 is on an H‐2‐like molecule which also carries the determinant recognized by the monoclonal antibody B22‐249R1, specific for the H‐2Db antigen. Unlike B22‐249R1, however, W6/32.1 does not bind to normal H‐2b lymphocytes, nor to a variety of tumor cell lines of the H‐2b haplotype. This crossreaction is specific to W6/32.1, and is not shared by other monoclonal antibodies of similar anti‐HLA specificities. Moreover, the affinity of W6/32.1 for its human antigen is substantially higher than for its mouse antigen. We conclude that W6/32.1 fortuitously recognizes a novel determinant on the H‐2Db antigen of MBL‐2, rather than an extensive region of structural homology shared between HLA and H‐2. Thus for cells of the H‐2b allotype this determinant is detected only on MBL‐2, and by definition is thus an example of a tumor‐associated antigen.
Alteration of immunologic function through early ontogenetic experiences Selective inactivation of T15‐positive B cells in neonatal mice is related to receptor avidity and is independent of thymus function
Authors: Etlinger Howard M. , Heusser Christoph H.
Published: February 2007

The immunologic effects initiated by injecting neonatal mice with phosphorylcholine (PC)‐protein conjugates were analyzed. Pretreated nude or thymus‐bearing mice produced greater proportions of low‐avidity, TEPC 15‐negative antibody than control animals when challenged as adults with thymus‐dependent (TD) or ‐independent (TI) PC‐conjugated antigen. Furthermore, pretreatment had a greater inhibitory effect on responses elicited by TD compared with TI antigen. These results demonstrate that exposure of neonatal mice to PC‐protein conjugates results in the selective inactivation of higher avidity, T15‐positive, PC‐reactive B cells; this process is independent of thymic function and the duration of hyporesponsiveness is linked to the relative T dependency of the challenge antigen.
Intra‐H‐2 and T cell requirements for the induction of maximal positive and negative allogeneic effects in vitro
Authors: Rolink Anton G. , Van Der Meer Walter , Melief Cornelis J. M. , Gleichmann Ernst
Published: February 2007

Cultures of T cell‐depleted mouse spleen cells (B cells) were reconstituted with either allogeneic or syngeneic untreated T cells. The primary (day 4) antibody‐forming cell responses to sheep red blood cells were then compared. In almost all combinations and regardless the nature of the H‐2 incompatibility between the T and B cells tested, small numbers of untreated allogeneic T cells provided better help [positive allogeneic effect (AE)] than the same numbers of syngeneic T cells; only in the combination in which B10.A(2R) T cells were added to B10.A(4R) B cells (differing at I‐B, I‐J, and S), no AE at all appeared. A strong positive AE was induced when the incompatibility included or consisted of I‐A. A strong positive AE was also induced across an I‐E difference, provided the B cells expressed the Eα molecule on the cell surface and did not differ at K/D. A negative AE only occurred when the H‐2 incompatibility on the B cells included or consisted of a difference at the K and/or D locus.

In contrast to untreated T cells, anti‐Lyt‐1 plus complement‐treated T cells induced neither a positive nor a negative AE. T cells treated with anti‐Lyt‐2 plus complement, too, were incapable of inducing a negative AE; instead, addition of anti‐Lyt‐2‐treated T cells to B cells that differed either at all of H‐2, at K plus I‐A, or at I‐a alone consistently led to the induction of a strong positive AE. Only a syngeneic‐like response was induced, however, when anti‐Lyt‐2 and complement‐treated T cells were added to B cells differing solely at the K locus.
Immune responses to xanthan gum I. The characteristics of lymphocyte activation by xanthan gum
Authors: Ishizaka Shigeaki , Sugawara Isamu , Hasuma Tadayoshi , Morisawa Seiji , Möller Göran
Published: February 2007

Xanthan gum (XG), a microbial polysaccharide produced extracellularly by fermentation of Xanthomonas campestris, has unique physical properties. We studied the effects of XG on murine lymphocytes in vitro and found that XG induced both a significant increase of DNA synthesis in mouse splenic B cells and thymocytes as well as polyclonal IgM and IgG antibody responses in B cells. XG‐activated thymocytes, however, did not display helper or suppressor functions. XG was almost as effective in inducing polyclonal antibody responses as lipopolysaccharide (LPS) in murine systems. Hamster spleen cells, however, were weakly triggered to nonspecific antibody production by XG but they were not triggered at all by LPS. Spleen cells from normal neonatal mice and from adult CBA/N mice, a strain which possesses an X‐linked defect affecting B cell differentiation, responded relatively well to XG and LPS, suggesting that XG can stimulate immature B cells as well as LPS does. It was found that XG activated B cells in the relative absence of T cells and macrophages. Spleen cells from LPS‐nonresponder C3H/HeJ mice and seven other mouse strains were stimulated to polyclonal antibody production by XG. In contrast, spleen cells from C57BL/10 mice were unresponsive or only slightly responsive to XG, but fully responsive to LPS.
Antibody response of mice following neonatal treatment with a monoclonal anti‐receptor antibody. Evidence for B cell tolerance and T suppressor cells specific for different idiotopic determinants
Authors: Cerny Jan , Cronkhite Richard , Heusser Christoph
Published: February 2007

BALB/c mice were injected neonatally with monoclonal antibody against a T15 idiotope, MaId5‐4, and the immune potential of splenic lymphocytes against phosphorylcholine (PC) was studied by stimulation with S. pneumoniae R36a (Pn) in vitro. The total number of PC‐specific plaque‐forming cells (PFC) and the proportion of PFC expressing the MaId5‐4 idiotope (Id+ PFC), as well as two other distinct (nonhomologous) idiotypes of the T15 family recognized by monoclonal antibodies AB1‐2 and B36‐82, was determined by plaque assay against PC‐coupled red blood cells. The magnitude of the total PFC response of splenocytes from age‐matched normal and MaId5‐4‐suppressed mice was comparable but all three Id(s) which were expressed on > 70% PFC from normal splenocytes were below detection level in splenocytes from suppressed mice. Depletion of T cells lowered the total PFC response to a comparable degree in both mice. Normal B cells (BN) stimulated by Pn expressed all three Id(s) much like the normal splenocytes. B cells from MaId5‐4‐suppressed mice (Bs) always failed to express MaId5‐4 but they occasionally did express the B36‐82 or Ab1‐2. The reciprocal mixing of B and T cells followed by Pn stimulation revealed that both normal T cells (TN) and T cells from MaId5‐4‐suppressed mice (Ts) provided equal help to either BN or Bs in regard to total PFC number. Ts consistently inhibited the expression of MaId5‐4 in BN cultures, but only rarely the expression of Ab1‐2 and B36‐82. Bs cocultured with TN never expressed MaId5‐4 but they sometimes did express one or both of the other two Id. These results show that neonatal application of a monoclonal anti‐Id suppresses the expression of the Id determinant which is recognized by the antibody, as well as other determinants. The mechanism of the suppression of the target Id (MaId5‐4) involves both B cell tolerance and active suppression. The mechanism of cosuppression (idiotopes AB1‐2 and B36‐82) is variable, apparently involving a B cell tolerance, lack of Id‐specific help, and/or active suppression.
Human large granular lymphocytes contain an esterase activity usually considered as specific for the myeloid series
Authors: Heumann Didier , Colombatti Marco , Mach Jean‐Pierre
Published: February 2007

A cytochemical marker such as alpha‐naphthyl acetate esterase (ANAE) has been found useful for the morphological identification of the subset of T lymphocytes having receptors for Fcμ (TM cells). ANAE reaction on TM cells gives a typical pattern of one to four positive spots, whereas this pattern is not found on T cells with receptors for Fcγ (TG cells). ANAE is abundant in monocytes but not detectable in granulocytes. Herein another type of esterase activity, naphthol‐AS‐D chloroacetate esterase (NCAE), is described; it is known to be abundant in granulocytes and was found to give a specific pattern of reactivity with the subpopulation of large granular lymphocytes (LGL). This pattern of fine granular staining was observed not only on LGL present in the TG cell subpopulation but also in LGL present in the non‐T, non‐B cells.

Fractions of peripheral blood mononuclear cells which were ènriched up to 80% in LGL by Percoll discontinuous density gradient gave a similar percentage of specific NCAE pattern. In addition, among the different fractions from Percoll gradient, there was a good correlation (r = 0.94) between the number of NCAE‐positive cells and the natural killer activity against the natural killer susceptible K562 target cells. It will be important to determine whether or not this enzymatic activity plays a role in the cytotoxic activities of LGL.
H‐2D products do not affect lysis of Kk target cells by Kk‐specific cytotoxic T cells
Authors: Teh Hung‐Sia , Romaniuk Roman , Von Boehmer Harald
Published: February 2007

Antigens coded by the major histocompatibility complex (MHC) stimulate a large number of cytotoxic T lymphocyte (CTL) precursors. Matzinger and Bevan have suggested that the high alloreactivity is a result of the formation of interaction antigens between MHC and non‐MHC‐coded antigens. Previous work by Langhorne and Fischer Lindahl did not support this hypothesis. In this report we describe an improved culture system to show that the recognition of Kk target cells by Kk‐specific clones is also unaffected by H‐2D products. Using such a culture system, which controls for the induction of nonspecific CTL by interleukin 2 (T cell growth factor), we were also able to confirm the original conclusion of Langhorne and Fischer Lindahl that polymorphic minor histocompatibility antigens do not significantly contribute to putative “interaction antigens” formed by MHC and other antigens.
Immunoglobulin C gene expression. IV. Alternative control of IgG1‐producing cells by helper cell‐derived B cell‐specific growth or maturation factors
Authors: Coutinho Antonio , Pettersson Sven , Ruuth Erik , Forni Luciana
Published: February 2007

The influence of helper cell‐derived B cell‐specific growth or maturation factors in the membrane expression and secretion of IgG1 and IgG3 isotypes among lipopolysaccharide‐activated B cell blasts was studied in mass cultures and in single clones. The results demonstrate that helper cells regulate IgG1 expression by two alternative modes: growth‐promoting factors expand membrane IgG1‐bearing nonsecretory activated B cells, while maturation factors induce terminal differentiation to high‐rate secretion of IgG1 in previously switched cells.

Apart from the isotype specificity in the maturation‐inducing signals for activated B lymphocytes, the present experiments demonstrate that isotype control by helper cells is intimately connected to the control of proliferation vs. terminal maturation in proliferating B cell populations.
Homologies between cell interaction molecules controlled by major histocompatibility complex‐ and Igh‐V‐linked genes that T cells use for communication; both molecules undergo “adaptive” differentiation in the thymus
Authors: Yamauchi Katsumi , Flood Patrick M. , Singer Alfred , Gershon Richard K.
Published: February 2007

We have previously described two types of immunoregulatory interactions between T cell subsets; in one an Ly‐1; I‐J+ inducer cell makes a soluble product (Ly‐1 T suppressor inducer factor, TsiF) that is also I‐J+ and which activates the effector cells of a suppressor circuit. Under normal circumstances the Ly‐1 TsiF activity is restricted by Igh‐V‐linked genetic polymorphisms. However, we now find the genotype of the inducer cell does not control this restriction. The inducer cell acquires a new Igh‐V‐linked self repertoire if it (“adaptively”) differentiates in an appropriate F1 radiation chimera or in an F1 thymus graft in a homozygous nude mouse. Conversely, cells from F1 mice cannot acquire this “dual” self repertoire if the host in which they differentiate does not express the relevant selecting structure(s).

A previously demonstrated H‐2‐restricted suppressor factor (Ly‐2 T suppressor factor) has also been examined and it is shown that this molecule is subject to the same differentiation constraints as is the Igh‐V‐linked restricted factor except, or course, in this case H‐2‐linked genes are the “restricting” elements. Thus, Igh‐V restrictions are related to major histocompatibility complex (MHC) restrictions in the parameter that has been termed “adaptive” differentiation.

The results also imply that the I‐J‐marked Igh‐V‐linked self recognition molecule(s) has a variable and constant region, since the adaptively differentiated molecules that show a new self recognition specificity retain the genetic I‐J polymorphism of the mice that supplied the bone marrow precursor cells and not the one of the thymus in which they differentiated.

It may be considered surprising to find a structure in the thymus that acts to select MHC‐positive molecules that see Igh‐V‐linked structures as self. The F1 into parent experiments make it unlikely that the thymus is passively armed by circulating molecules that might act as the selecting elements. Since there is such a striking parallelism in the “adaptive” differentiation of cells that recognize Igh‐V and MHC as self, one must consider the possibility that Igh‐linked gene products are expressed by cells in the thymus and function there to select for those Ly‐1 TsiF producer cells that can recognize these Igh‐V‐linked cell interaction structures as self.
Molecular characterization of a nonsecreting myeloma mutant
Authors: Argon Yair , Burrone Oscar R. , Milstein César
Published: February 2007

The nonsecreting myeloma mutant, NSII/1, derived from MOPC 21 a mouse myeloma cell line, does not produce L chains and expresses a smaller than normal γ1 heavy chain, H* (Cowan, Secher and Milstein, J. Mol. Biol. 1974. 90: 691). The free H* is not secreted, but secretion can be rescued in hybrids expressing a light chain. By sequencing L and H chain‐cloned cDNA derived from NSII/1 we find only one light chain mRNA expressed which belongs to an aberrantly rearranged kappa gene. We also find that the H* heavy chain is the result of a point mutation. H* mRNA contains an A instead of the G found in wild type at position 1125. The corresponding tryptophan 406 becomes a chain termination, giving rise to a 67 amino acid deletion at the C‐terminus. The H* is core‐glycosylated, but its state of assembly is abnormal: H* forms high molecular weight, S–S‐bonded complexes. The results are discussed with reference to the putative toxic properties of free heavy chains and the failure of some chains to be secreted.
Inhibition of glycosylation prevents H‐2K and D antigen expression on SV40 virus‐transformed cells
Authors: Swaminathan Sankar , Gooding Linda R.
Published: February 2007

Tunicamycin, an inhibitor of glycosylation, was used to examine the role of carbohydrate moieties of glycoproteins involved in recognition of Simian virus 40 (SV40)‐transformed cells by cytotoxic T lymphocytes (CTL). Tunicamycin treatment renders such cells refractory to lysis by H‐2 restricted, SV40‐specific CTL as well as by allogeneic CTL directed only against H‐2 antigens. Treated cells are no longer susceptible to lysis by anti‐H‐2 antisera and complement, nor are they stained by monoclonal anti‐H‐2 antibodies in an indirect immunofluorescence assay. No accumulation of H‐2 proteins was detected in immunoprecipitates from cells labeled with [35S]methionine in the presence of tunicamycin. It is concluded that tunicamycin prevents the expression of H‐2 glycoproteins in these cells, perhaps due to accelerated degradation of the unglycosylated molecules.
Are “natural killer” cells involved in allograft rejection?
Authors: Nemlander Arto , Saksela Eero , Häyry Pekka
Published: February 2007

“Natural killer” (NK) effector cells and large granular lymphocytes (LGL) are found inside rat renal allografts during rejection. Their appearance in situ precedes the appearance of cytotoxic T lymphocytes, and concomitantly with their influx in the allograft, the NK activity and the LGL are depleted from the recipient spleen. This suggests that the NK effector cells and the LGL are involved in allograft rejection, although their role(s) among the other in situ inflammatory effector pathways remains to be clarified.
Antigenic markers of V domain of mouse MOPC 21 IgG1 L chain. The conformational basis of VL domain markers and content of MOPC 21 VL‐like immunoglobulins in sera of inbred mouse strains
Authors: Rokhlin Oscar V. , Petrosyan Margarita N. , Ibraghimov Alexander R. , Vengerova Tamara I. , Bogachova Galina T.
Published: February 2007

Antisera were raised in rabbits against L chains, isolated from mouse myeloma protein MOPC21 (γ1,x, Vx15 group). Specific antibodies for the V and C domain of MOPC 21 L chain were obtained by cross‐immunoadsorption of the antisera. The pure anti‐V and anti‐C antibodies were fixed on diazocellulose and used as immunosorbents. The inhibitory capacity of L chain‐monomers and dimers isolated from the L chain preparation was compared to that of intact IgG1 using binding inhibition of 125I‐labeled IgG1 on the antibody‐containing immunosorbents. It was established that changes of IgG1 quaternary structure influences the conformational state of the L chain V domain only. The inhibitory capacity of the V domain is 1000‐fold lower in L monomers, if compared with native IgG1, and only 10‐fold lower than in L dimers. The inhibiting capacity of the C domain, however, does not differ in L monomers and intact IgG1. Thus the conformational rigidity of the C domain co‐exists with conformational flexibility of the V domain on the same polypeptide chain. We tried to estimate the content of MOPC 21 VL‐like normal IgG in mouse serum of 6 inbred strains using antibodies against the VL domain. Data obtained by inhibition of radioimmunoadsorption, indicate that in C57BL/6 mice 0.08% of normal serum Ig carries a VL region which is idiotypically related to the VL of MOPC 21. In serum Ig of BALB/c mice the percentage is 0.16.
T cell‐mediated cytolysis: on the strength of effectortarget cell interaction
Authors: Bongrand Pierre , Pierres Michel , Golstein Pierre
Published: February 2007

Allosensitized lymphoid cell populations contain T lymphocytes that can bind to target cells and lyse them. We asked whether there was a relationship between lymphocyte target cell‐binding strength and occurrence of cytolysis. Using graded shear forces to dissociate effector‐target cell conjugates, we found that (a) within an allosensitized lymphoid cell population derived from an heterogeneous mixed leukocyte culture, there were lymphocyte‐target cell conjugates with binding strengths differing by a factor of at least 102, (b) even the minimal force required to release a significant amount of bound target cells could disrupt the plasma membranes of some tumor cells and (c) these tumor cells disrupted by shear forces were probably part of cytolysis‐conducive rather than of non‐cytolysis‐conducive conjugates.

We combined this approach with the use of cytolysis‐inhibiting monoclonal antibodies (mAb), and found that antibody‐induced decrease of cytolysis was correlated with a decrease in the percentage of strong or total conjugates, depending on the mAb used. When lectins were added to overcome the inhibitory effect of the mAb, reappearance of cytolytic activity correlated with reappearance of conjugates. This was especially striking using wheat germ agglutinin (WGA): the addition of WGA to irrelevant effector‐target cell combinations did not lead to cytolysis; however, the addition of WGA to relevant effector‐target cell combinations inhibited by mAb led to reappearance of cytolysis and of strong conjugates. Taken together, these and other results suggested that under our experimental conditions a threshold level of binding strength between effector and target cells might be important, although not sufficient, for T cell‐mediated cytotoxicity. These results were not inconsistent with the involvement of mechanical factors in this process. Also, they were in line with the concept of nonantigen‐specific lymphoid cell surface interacting molecules, detected by the mAb used and important for the establishment of strong, functional lymphocyte target cell interactions. Finally, they underlined the necessity of a quantitative estimate of cell‐cell binding strength when investigating the effect of a given agent (e.g. a mAb) on lymphocyte target cell recognition.
Committed precursors of B and T lymphocytes in chick embryo bursa of Fabricius, thymus, and bone marrow
Authors: Brand Ann , Galton Jane , Gilmour Douglas G.
Published: February 2007

Lymphocyte precursors in bursa of Fabricius, thymus and bone marrow (BM) of chick embryos were studied at different stages of incubation over 12–21 days, and for their state of commitment to B or T cell lines of development. Cell suspensions were fractionated on albumin gradients to remove nonlymphoid cells and incubated in vitro with bursopoietin, a specific inducer of B cells, or crude chicken thymus extract, a specific inducer of T cells, or ubiquitin, a nonspecific inducer. Precursors were identified by increases in numbers of cells bearing surface alloantigens as determined by immunofluorescence, either Bu‐1 (specific to B cells) or Th‐1 (specific to T cells). Precursors inducible to Bu‐1+ cells were found in bursal cells and BM cells from all age groups but not in thymic cells. Precursors inducible to Th‐1+ cells were found in thymic preparations and BM cells at all ages, but in significant numbers in bursa on day 12 only. Because B and T precursors were never found together in bursa or thymus, or only in very unequal amounts, it was concluded that precursors in these organs were not multipotential but were separately committed to one or other line of development. This argument did not apply to BM cells, for which other evidence was obtained. Bu‐1+ cells were specifically induced in BM cells with bursopoietin and then removed by complement‐dependent cytolysis with anti‐Bu‐1 antiserum. When the remaining cells were incubated with ubiquitin, only Th‐1+ cells were induced, showing that Bu‐1 and Th‐1 precursors were separately committed. Surface IgM was never induced on either bursal or BM lymphocytes. The Ia (or B‐L) antigen was inducible on 12‐ to 21‐day bursal cells, but could not be generated on BM cells until day 14 onwards. The pattern of occurrence of committed lymphocyte precursors in the developing chick embryo suggests that these cells are released into the circulation from both central lymphoid organs at their respective times of high lymphopoietic activity, and accumulate in the BM at least up to the time of hatching. Moreover, the presence of committed B precursors in bursa and committed T precursors in thymus at times and in quantities appropriate to the known features of avian lymphopoiesis leads us to conclude that in vitro induction is analogous to a true stage of in vivo B and T cell differentiation.
A monoclonal antibody (100C5) to the Lyt‐2− T cell population expanding in MRL/Mp‐lpr/lpr mice detects a surface antigen normally expressed on Lyt‐2+ cells and B cells
Authors: Dumont Francis J. , Habbersett Robert C. , Nichols Elizabeth A. , Treffinger Jacqueline A. , Tung Amar S.
Published: February 2007

MRL/Mp‐lpr/lpr (MRL‐lpr) mice develop a generalized lymphadenopathy reflecting the expansion of a Lyt‐2− T cell population. The present report describes the pattern of reactivity of a xenogeneic monoclonal antibody (mAb 100C5) directed against this T cell population. By single‐ and two‐color flow cytofluorometry analysis this mAb was found to stain brightly 80–90% of T cells in enlarged MRL‐lpr lymph nodes. In contrast lymph node T cells from congenic MRL‐MP‐+/+ (MRL‐+) mice were either unstained (70%) or weakly stained (30%), these latter cells being mostly Lyt‐2+. Unexpectedly, all lymph node B cells from MRL‐+ or MRL‐lpr mice were as strongly 100C5+ as MRL‐lpr T cells. Similar observations were made in C57BL/6‐lpr/lpr and C57BL/6‐+/+ mice. Molecular weight determination suggested that the 100C5 mAb binds to the same molecule (Mr = 220000) on MRL‐lpr T cells and normal B cells.
Anti‐idiotypes against anti‐H−2 antibodies VI. Detection of shared idiotypes among monoclonal anti‐H−2 antibodies
Authors: Bluestone Jeffrey A. , Auchincloss Hugh , Sachs David H. , Fibi Matthias , Hämmerling Günter J.
Published: February 2007

Anti‐idiotypes produced against monoclonal anti‐H‐2 antibodies have been used to examine idiotope sharing among a panel of anti‐major histocompatibility complex (MHC) antibodies detecting the same and different specificities. Both xenogeneic anti‐100‐30 and anti‐3‐83, which did not react with predominant idiotypes in conventional alloantisera, detected shared idiotopes on 3‐83 and 100‐30 as well as on 2 other monoclonal anti‐H‐2Kk antibodies. All 4 monoclonal antibodies recognized the same epitope cluster on the Kk molecule and detected the same serological specificity, H‐2.5. In contrast, syngeneic and allogeneic anti‐idiotype produced against the same monoclonal antibodies did not detect these cross‐reactive determinants. In several instances, xenogeneic anti‐idiotype reacted with anti‐MHC antibodies which recognized distinct H‐2 determinants, suggesting that anti‐MHC antibodies detecting the same or different specificities may share idiotypic determinants. These reagents may be useful probes of the anti‐MHC immune repertoire.
Two monoclonal antibodies identifying a subset of human peripheral mononuclear cells with natural killer cell activity
Authors: Bai Yan , Beverley Peter C. L. , Knowles Robert W. , Bodmer Walter F.
Published: February 2007

Two monoclonal antibodies (H25 and H366) raised against the cultured T lymphoid cell line HSB‐2 were shown to define a subset of peripheral mononuclear cells with natural killer and killer cell activity. The two antibodies show similar tissue distributions. Radioimmune trace binding assay shows that H25 and H366 react with all T cell lines tested and with the monocyte line U937, but weakly or not at all with cell lines of B, myeloid or erythroid origin. Both antibodies react with about 10% of E rosetteforming cells and a proportion of nonrosetting lymphocytes and monocytes. They do not react with B lymphocytes, granulocytes, red cells or platelets. A proportion of thymocytes and low numbers of tonsil and spleen mononuclear cells are positive. H25+ and H366+ lymphocytes are medium‐sized cells with abundant granular cytoplasm, and most carry Fc receptors for IgG. H25 and H366 immunoprecipitate two polypeptide chains of 96 and 53kDa from surface‐labeled HSB‐2 cells.
Monoclonal anti‐VH antibodies recognize a common VH determinant expressed on immunoglobulin heavy chains from various species
Authors: Eshhar Zelig , Gigi Orit , Givol David , Ben‐Neriah Yinon
Published: February 2007

Our previous work using rabbit antibodies to the variable region of MOPC315 myeloma heavy chain (VH) has indicated the existence of framework determinant(s) common to many murine heavy chains. Here we report the characterization of anti‐VH monoclonal antibodies (mAb) prepared in an attempt to elucidate the nature of the common VH determinant. We immunized AKR/J mice with a purified VH315 fragment and generated somatic cell hybrids by the fusion of the immune AKR/J splenocytes with the NS1 myeloma cells. Thirty‐seven common anti‐VH and 57 subgroup VHI‐specific hybridomas have been established and characterized. Whereas the anti‐subgroup mAb seemed to react with a determinant unique to the MOPC315 (mouse VHI) subgroup, all the anti‐VH mAb reacted with myeloma heavy chains of different VH subgroups, class and allotypes. Antibody competition studies revealed that the VH subgroup determinants are distinct from the common VH determinants and that both were also recognized by the rabbit polyclonal antibodies. The common VH determinants were found to be “hidden” determinants on intact immunoglobulin molecules being exposed only on isolated heavy chains. Furthermore, they are sequential determinants since they are preserved on fully denatured heavy chains. The common VH determinants are shared by immunoglobulins of a wide range of vertebrates from amphibia to man and thus represent antigenic structures which were highly conserved throughout evolution.
Characterization of chicken T cell growth factor
Authors: Schnetzler Marianne , Oommen Anna , Nowak Jerzy S. , Franklin Richard M.
Published: February 2007

Chicken spleen and peripheral blood lymphocytes were tested for their ability to produce T cell growth factor (interleukin 2, IL2) upon stimulation with phytohemagglutinin or concanavalin A (Con A). Using a qualitative microassay, peak activity was found in 24‐h supernatants of mitogen‐stimulated lymphocytes. These supernatants permitted continuous growth of chicken lymphocytes for several weeks and increased the Con A response of chicken thymocytes. A quantitative probit microassay was developed and used in the further studies when appropriate. Chicken IL2 binds specifically to thymocytes and activated T cells and its action upon T blast cells cannot be blocked by cyclosporin A. The molecular weights of the two biological active peaks found by gel filtration of the native IL 2 preparation were in the range 19500‐21500 and 9000‐11500. A single polypeptide of molecular weight 13000 was found by gel electrophoresis under reducing conditions.
Immunoglobulin heavy chain class switch from IgM to IgG in a hybridoma
Authors: Thammana Pallaiah , Scharff Matthew D.
Published: February 2007

A subclone of an IgM‐producing hybridoma has been identified which has switched to producing an IgG1 antibody. The parent hybridoma, PC‐140, produces an antibody which binds phosphorylcholine and reacts with monoclonal antibodies that recognize myelomas of the T‐15 idiotype. The IgG1 antibody binds phosphorylcholine with the same affinity as the parental IgM and also reacts with the anti‐T‐15 monoclonal antibodies. While the IgM‐producing parent hybridoma does not express detectable surface IgM, the IgG1‐producing subclone produces both membrane and secreted IgG1.
The mechanism of synergistic complement‐mediated lysis of rat red cells by monoclonal IgG antibodies
Authors: Hughes‐Jones Nevin C. , Gorick Barbara D. , Howard Jonathan C.
Published: February 2007

The mechanism of synergistic complement‐mediated lysis of rat red cells was investigated using rat monoclonal antibodies against class IR1Aa antigens. The increased lytic activity when using two antibodies simultaneously is due to the increase in the number of activated C1 molecules on the cell surface and this results from (a) an increase in the number of binding sites for C1q, (b) an increase in the functional affinity constant for C1q binding and (c) an increase in the rate of activation of C1. Complete lysis of red cells was only achieved if one member of the synergistic pair was of the γ2b isotype, and this isotype weas the only one to which binding of 125I‐labeled C1q could be detected. A partial synergistic effect was seen using an F(ab′)2 fragment of antibody. Increased uptake and activation of C1 probably results both from the presence of two antibodies attached to each antigen molecule and from the formation of antigen‐antibody catenars.
Biological and biochemical characterization of an interleukin 1‐like factor from rat C6 glioma cells
Authors: Fontana Adriano , McAdam Keith P. W. J. , Kristensen Flemming , Weber Elisabeth
Published: February 2007

It has been previously reported that lipopolysaccharide‐stimulated murine astrocytes produce a factor which enhances the proliferative response of thymocytes to lectins. The present report demonstrates that a rat astrocytoma cell (C6 cells)‐derived factor appears to be similar to macrophage‐derived interleukin 1 (IL1) in its biological activities and biochemical characteristics. Upon injection into mice, supernatants of C6 cells induce the production of serum amyloid A. The C6 cell‐derived factors enhance the response of thymocytes to phytohemagglutinin and the growth of fibroblasts whereas no effect on the growth of neuroblasts and of a strictly interleukin 2 (IL2)‐dependent T cell line was observed. On an AcA 54 column the C6‐derived factors acting on thymocytes and fibroblasts coeluted as a single peak of Mr> = 13500 to 18000; the semipurified factor was found to enhance the lymphocytes' production of IL2. These observations demonstrate that cells not belonging to the mononuclear phagocyte lineage are able to produce factors identical or closely related to IL1.
The analysis of an anti‐fluorescein cytotoxic response
Authors: Christensen Neil , Skinner Margot , Marbrook John
Published: February 2007

The detailed kinetics of the appearance of clones of anti‐fluorescein cytotoxic T lymphocytes (CTL) in a primary limiting dilution response have been examined. The addition of factors from the supernatants of concanavalin A‐stimulated rat spleen cell cultures was necessary to obtain linear dose‐response curves and strong primary responses. In a standard primary response the maximum detectable number of specific clones was found, on day 5, to be derived from precursors having a frequency of 1 in 10000 spleen cells. When limiting dilution cultures were restimulated on day 3, responses on day 5 were unaffected but new clones appeared on day 7 with a frequency of 1 in 1000. The emergence of the day‐7 response depends on the addition of factor(s) on day 3. It is proposed that the early low frequency precursors detected on day 5 and the high frequency precursors detected on days 7–9 are derived from two stages in the differentiation lineage of CTL precursors. Restimulation of limiting dilution cultures involves not only the continued clonal expansion of primary responses but also the emergence of new “clones” of specific CTL.
Diversity in the biological properties of anti‐influenza cytotoxic T cell clones
Authors: Taylor Patricia M. , Askonas Brigitte A.
Published: February 2007

This study reports the examination of in vivo and in vitro properties of an antigendependent murine cytotoxic T cell (Tc) clone T5/5 specific for type A influenza virus. This clone differs morphologically and in its migratory pattern and biological properties from a previously examined anti‐influenza Tc clone L4 which grew in T cell growth factor independently of antigen. Unlike Tc clone L4, T5/5 cells do not release significant amounts of immune interferon on contact with influenza‐infected target cells nor do they limit virus replication in vivo, although they efficiently lyse influenza‐infected target cells and can release interferon in the presence of concanavalin A. Thus individual Tc clones vary in function and further work is required to establish the properties of Tc that are associated with host protection against virus infection.
Idiotypic and fine specificity analysis of a (4‐hydroxy‐3‐nitrophenyl)acetyl (NP)‐specific suppressor T cell hybridoma at the level of cell surface structures, isolated receptor material and functional suppressor factor
Authors: Suzuki Gen , Cramer Matthias , Hayakawa Kyoko , Okumura Ko , Tada Tomio
Published: February 2007

The (4‐hydroxy‐3‐nitrophenyl)acetyl (NP)‐specific T suppressor cell hybridoma 7C3‐13 was established by fusing splenic B10.BR T cells enriched on NP‐coated petri dishes with the AKR thymoma BW5147. 7C3‐13 was selected by anti‐NPb idiotypic and anti‐I‐Jk antibodies in microcytotoxicity tests. The hybridoma expressed H‐2k, I‐Jk, Qa‐1, Thy‐1.1 as well as idiotypic (binding site‐related) and framework Ig VH determinants, while it was negative for I‐A, I‐E/C, Thy‐1.2, Lyt‐1, Lyt‐2 and Ig constant region determinants. Hapten‐binding receptor material could be isolated from 7C3‐13 cells on NP‐coupled nylon nets and functionally active T suppressor factor (TsF) could be extracted from the hybridoma. Both types of soluble molecules express NPb idiotype, but the TsF carries I‐J determinants in addition while the isolated receptors do not. The molecular weight of the isolated receptor material is 80000, that of the TsF activity is 27000 and 57000–64000, respectively. We thus were able to show that NP‐binding molecules can be obtained in the form of cellular surface receptors, isolated receptor material and extracted TsF from one and the same, monoclonal, cell source.
Demonstration of the stability of the membrane phenotype of T helper cells after priming and boosting with a hapten‐carrier conjugate
Authors: Spickett Gavin P. , Mason Don W.
Published: February 2007

Evidence is presented that the phenotype of the rat T helper cells is stable after priming and boosting with a hapten‐carrier conjugate and that the phenotype is W3/25+, MRC OX‐22−, MRC OX‐8−. Data are also presented that demonstrate the presence of doubly marked, W3/25+, MRC OX‐8+, cells in the spleens of rats primed 1 week previously.