Siderophore protection against colicins M, B, V, and Ia in Escherichia coli.

A variety of natural and synthetic siderophores capable of supporting the growth of Escherichia coli K-12 on iron-limited media also protect strain RW193+ (tonA+ ent-) from the killing action of colicins B, V, and Ia. Protective activity falls into two categories. The first, characteristic of enterobactin protection against colicin B and ferrichrome protection against colicin M, has properties of a specific receptor competition between the siderophore and the colicin. Thus, enterobactin specifically protects against colicin B in fes- mutants (able to accumulate but unable to utilize enterobactin) as predicted by our proposal that the colicin B receptor functions in the specific binding for uptake of enterobactin (Wayne and Neilands, 1975). Similarly ferrichrome specifically protects against colicin M in SidA mutants (defective in hydroxamate siderophore utilization). The second category of protective response, characteristic of the more general siderophore inhibition of colicins B, V, and Ia, requires the availability or metabolism of siderophore iron. Thus, enterobactin protects against colicins V and Ia, but only when the colicin indicator strain is fes+, and hydroxamate siderophores inhibit colicins B, V, and Ia, but only when the colicin indicator strain is SidA+. Moreover, ferrichrome inhibits colicins B, V, and Ia, yet chromium (III) deferriferrichrome is inactive, and ferrichrome itself does not prevent adsorption of colicin Ia receptor material in vitro. Although the nonspecific protection against colicins B, V, and Ia requires iron, the availability of siderophore iron for cell growth is not sufficient to bring about protection. None of the siderophores tested protect cells against the killing action of colicin E1 or K, or against the energy poisons azide, 2, 4-dinitrophenol, and carbonylcyanide m-chlorophenylhydrazone. We suggest that nonspecific siderophore protection against colicins B, V, and Ia may be due either to an induction of membrane alterations in response to siderophore iron metabolism or to a direct interference by siderophore iron with some unknown step in colicin action subsequent to adsorption.     

Ca(2+)-calmodulin-dependent protein kinases Ia and Ib from rat brain I. Identification, purification, and structural comparisons.

Two Ca(2+)-calmodulin (CaM)-dependent protein kinases were purified from rat brain using as substrate a synthetic peptide based on site 1 (site 1 peptide) of the synaptic vesicle-associated protein, synapsin I. One of the purified enzymes was an approximately 89% pure protein of M(r) = 43,000 which bound CaM in a Ca(2+)-dependent fashion. The other purified enzyme was an apparently homogenous protein of M(r) = 39,000 accompanied by a small amount of a M(r) = 37,000 form which may represent a proteolytic product of the 39-kDa enzyme. The 39-kDa protein bound CaM in a Ca(2+)-dependent fashion. Gel filtration analysis indicated that both enzymes are monomers. The 43- and 39-kDa enzymes are named Ca(2+)-CaM-dependent protein kinases Ia and Ib (CaM kinases Ia, Ib), respectively. The specific activities of CaM kinases Ia and Ib were similar (5-8 mumol/min/mg protein). CaM kinase Ia (but not CaM kinase Ib) activity was enhanced by addition of a CaM-Sepharose column wash (non-binding) fraction suggesting the existence of an "activator" of CaM kinase Ia. Both kinases phosphorylated exogenous substrates (site 1 peptide and synapsin I) in a Ca(2+)-CaM-dependent fashion and both kinases underwent autophosphorylation. CaM kinase Ia autophosphorylation was Ca(2+)-CaM-dependent and occurred exclusively on threonine while CaM kinase Ib autophosphorylation showed Ca(2+)-CaM independence and occurred on both serine and threonine. Proteolytic digestion of autophosphorylated CaM kinases Ia and Ib yielded phosphopeptides of differing M(r). These characteristics, as well as enzymatic and regulatory properties (DeRemer, M. F., Saeli, R. J. Brautigen, D. L., and Edelman, A. M. (1992) J. Biol. Chem. 267, 13466-13471), indicate that CaM kinases Ia and Ib are distinct and possibly previously unrecognized enzymes.     

Expression of Group B Protective Surface Protein (BPS) by Invasive and Colonizing Isolates of Group B Streptococci

Group B protective surface protein (BPS) is expressed on the cell surface of some group B streptococcal (GBS) (Streptococcus agalactiae) strains and adds to the identification by capsular polysaccharide (CPS), and c or R proteins. We investigated the prevalence of BPS among GBS clinical isolates (303 invasive, 4122 colonizing) collected over 11 years in four American cities. Hot HCl cell extracts were tested by immunoprecipitation in agarose with rabbit antisera to BPS; the alpha (α) and beta (β) components of c protein; R1, R3, and R4 species of R protein; and CPS serotypes Ia–VIII. BPS was found in 155 isolates (seven invasive, 148 colonizing). Of these, 87 were Ia, 37 II, 20 V; none were III. BPS was expressed usually with another protein: a species of R by 87 or a component of c by 39. The predominant CPS/protein profiles with BPS were Ia/R1,BPS and II/c(α + β),BPS. Thus, along with CPS serotype and other surface proteins, BPS can be a valuable marker for precise strain characterization of unique GBS clinical isolates with complex surface protein profiles.     

B lymphocyte alloantigens controlled by theI region of the major histocompatibility complex in mice

An antiserum was produced by reciprocal immunization of congenic resistent inbred strains of mice which differed only with respect to theI andS regions of theH- 2 complex. This antiserum permitted the serological detection of lymphocyte alloantigens, designated Ia (=I region associated antigens). Ia determinants are only present on mature B lymphocytes. They could not be found on thymocytes, splenic or lymph node T cells, or on the majority of bone marrow cells. Absorption studies demonstrated existence of several Ia specificities which are associated with differentI region types. Thus, theI region of theH- 2 complex appears to control not only T-cellexpressed antigen specific immune response genes, but also B-cell-expressed Ia determinants. The relevance of the Ia alloantigen system for cellular interaction in immune reactions is discussed.     

Isolation and characterization of murine Ia antigens

The isolation and characterization of Ia antigens from both lymphoid and nonlymphoid cells was attempted by SDS-polyacrylamide gel electrophoresis of radiolabeled, NP-40 solubilized, and anti-Ia precipitated lysates. The profiles obtained indicate that membrane proteins with a molecular weight of approximately 30,000 can be isolated from peripheral B but not from peripheral T cells. Ia antigens cannot be immunoprecipitated from cortisone-resistant thymocytes, total thymocytes, allogeneically activated T cells, Con A stimulated T cells, and anti-Ig immunoadsorbent purified T cells. Ia antigens seem to comprise only 1%–2% of labeled splenic intracellular and membrane-associated proteins. They differ from H-2 antigens and immunoglobulin H and L chains with respect to size and serological reactivity. Ia antigens cannot be found to be secreted from lymph node cells or splenocytes into the extracellular incubation media. Tissue distribution studies indicate that Ia antigens are present on macrophages, fetal liver cells, epidermal cells, and bone marrow cells. They have not been found on such tumor cells as myelomas, teratomas, and lymphocytic leukemias.     

M.M. Kamshilov's Informational–Biogeochemical Concept of Life

The broad interdisciplinary synthesis based on theoretical biology and biospheric ecology attempted by M.M. Kamshilov, a disciple of A.S. Serebrovsky, I.I. Schmalhausen, and V.I. Vernadsky, and his original informational–biogeochemical concept of life were described.     

Evidence for structural homology between murine and human Ia antigens

The serological cross-reactivity and the structural homology of murine and human Ia alloantigens were analyzed. Both normal human peripheral blood B lymphocytes and chronic lymphocytic leukemia (CLL) cells were shown to be lysed in the presence of complement by both murine anti-Ia and human anti-HLA-DR alloantisera. A mouse A.TH anti-A.TL (anti-I ^k ) alloantiserum reacted with determinants expressed on all of the 20 normal human B cell populations tested. Only 3 of these 20 B cell populations were lysed with an A.TL anti-A.TH anti-I ^s alloantiserum. The frequency of cytotoxic cross-reactivity concordant with anti-I ^k appears to be greater for anti-I-EC ^k than for anti-I-A ^k alloreactivity. An immunochemical analysis demonstrated that Iaα-chain andβ-chain polypeptides may be immunoprecipitated from CLL cell lysates by either a mouse anti-I ^k alloantiserum or various human anti-HLA-DR alloantisera. The Ia molecules detected with the mouse and human antisera are coprecipitable as revealed by one-dimensional gel electrophoresis. Two-dimensional gel electrophoresis studies indicated that the human CLL cell Ia antigens analyzed possess considerable molecular heterogeneity. They are structurally more similar, with respect to molecular size and charge, to mouse Ia antigens determined by the murineH-2-linkedI-EC subregion rather than theI-A subregion. The structural, genetic and functional implications of these findings are discussed.     

T(Iat)- and B(Iab)-cell alloantigens determined by theH-2 linkedI region in mice

The specificity of an antiserum directed againstI region associated (Ia) antigens is described. The serum was raised in (DBA/1×B10.D2)F₁ mice against lymphocytes of AQR mice, differing from the responder for theI region only. The serum reacts with Ia antigens expressed on B cells (Iab) as well as with Ia antigens expressed on T cells (Iat). Absorption studies indicate that B cells possess at least two Ia antigens, and one of these is shared by T cells. However, this shared antigen is not present on the surface of lymphocytes of thymectomized mice. Analysis of the strain distribution of Iab and Iat antigens revealed that the Iab antigens are present on lymphocytes of mice carrying theIA ^k subregion and that the Iat antigens are present on lymphocytes of mice carryingI region genes of theH-2 ^k haplotype located between theIA andIB subregions. This conclusion is based on the analysis of the antiserum's reactivity with T and B cells of the strains B10.A(2R), B10.A(4R) and B10.HTT: the serum reacts with B and T cells of B10.A(2R) but only with B cells of B10.A(4R) mice and only weakly with T cells of B10.HTT mice.Abbreviations ALG antimouse lymphocyte globulin from rabbits - B cells bone marrow derived lymphocytes - B10 C57BL/10Sn mice - D1D2F₁ (DBA/1×B10.D2)F₁ hybrid mice - GVHR graft-vs-host reaction - Ia I region associated antigen - Iab on B cells - Iat on T cells - MLR mixed lymphocyte reaction - T cells thymus-derived lymphocytes - Thy-1 thymus antigen 1, formerly called theta - Tx-Lyc lymphocytes of thymectomized, ALG treated, lethally irradiated and anti-Thy-1 treated bone marrow reconstituted mice - 2R B10.A(2R)/SgSn mice - 4R B10.A(4R) mice     

Enhanced in vitro cytotoxic anti H-2 responses in the presence of Ia antigens

Because surface Ig and Ia antigens cap independently, A.TH anti-A.TL serum combined with the indirect immunfluorescence technique could be used to test defined murine cell populations ofH-2 ^k haplotype for the presence of Ia antigens. Mitogen induced T- and B-cell derived blast cells, purified by velocity sedimentation at 1g, were tested for the expression of Ia^k antigens and then used both as stimulator cells and as target cells, in primary and secondary in vitro cytotoxic allograft responses. Fibroblasts, cortisone-resistant thymocytes, and nylon column purified splenic T cells were also included in these tests. Ia antigens were detected on 100% of LPS-induced blast cells, on 20%–30% of ConA-induced blast cells (100%Θ Thy-1 or antigen positive), but only to 5%–10% on PHA-blasts (100% Thy-1 antigen positive). Fibroblasts and nylon column purified splenic T cells were essentially Ia negative. Ia-positive allogeneic stimulator cells induced a far stronger in vitro cytotoxic T-cell response compared to Ia-negative stimulator cells; that is, there was a positive correlation between the expression of Ia antigens on the stimulator cells and the magnitude of cytotoxicity induced. This correlation was restricted to primary allograft responses. Ia antigens could not be detected as a target for killing in the cytotoxic effector phase, using both different target cells as well as the approach of “PHA dependent lysis” for detecting cytotoxic T lymphocytes.     

The role of experimental entomology in working out fundamental problems of physiology and medicine (L.A. Orbeli and experimental entomology)

This paper is based on the author’s lecture presented at the conference Theoretical and Applied Entomology: Past, Present and Future, dedicated to the 150th anniversary of the Russian Entomological Society, which took place on April 2, 2009 in St. Petersburg. The lecture suggested a definition of the concept “experimental entomology” and listed the most popular research objects. A brief historical review of the origin and development of some trends in experimental entomology in the XX and XXI centuries in Russia was given. Special attention was paid to the contribution of Acad. L.A. Orbeli and his ideas concerning evolution of functions and functional evolution as well as to the importance of ideas of his collaborators and followers, G.V. Gershuni, L.G. Leibson and A.L. Polenov, in developing a number of present directions of experimental entomology. These classic and ultramodern directions include comparative genetics of behavior (M.E. Lobashev, A.K. Voskresenskaya, N.G. Lopatina, I.A. Nikitina, V.B. Savvateev, V.V. Ponomarenko, N.G. Kamyshev), genetics of higher nervous activity (N.G. Lopatina), neurogenetics (E.V. Savvateeva-Popova), biorhythmology (ecological concept of photoperiodism—A.S. Danilevsky, investigation of the physiological mechanisms of photoperiodic adaptations—V.P. Tyshchenko), immunology (S.I. Chernysh), neuroendocrinology and mechanisms of stress (I.Yu. Raushenbach, S.I. Chernysh, G.V. Ben’kovskaya), psychoneuroendocrinology (the hypothesis of “dynamic neuroendocrine integration”—A.N. Knyazev), etc. A special place in the lecture was assigned to sensory physiology of insects and, first of all, to the series of monographs by F.G. Gribakin, Yu.A. Elizarov, G.A. Mazokhin-Porshnyakov, R.D. Zhantiev, A.V. Popov, V.L. Svidersky, A.V. Skirkyavichus, L.I. Frantsevich awarded the USSR State Prize in 1987. The origin of a novel field, cognitive ethology (Zh.I. Reznikova) that emerged at the intersection of ethology, ecology, theory of evolution, and comparative psychology is noted in the final part of the lecture.     

The Study of Children’s Play within the Context of Cultural-Historical Psychology: Experience and Prospects

The paper reconstructs the history of the problem of mental development using material from children’s play. This study shows how researchers in the school of cultural-historical psychology identified the developmental function of play, established a qualitative leap in its development and attempted to re-create it, beginning with the works of L.S. Vygotsky, then of his followers (the activity-based approach in the interpretation of narrative role-playing: A.N. Leontiev, D.B. Elkonin, N.Ia. Mikhailenko, N.A. Korotkova, etc.), and, finally, of the researchers who studied a specific act of development in play (L.I. El’koninova, T.V. Bazhanova, K.O. Iur’eva). This research presents the view that the concept of the cultural form of play, containing a Challenge (defined by the boundaries of the possibilities of action and by risk) and the subsequent Response is the basis not only of narrative role-playing but also of games with rules, as well as computer games. The Challenge entails action that changes the action situation; it typifies all forms of play, which are supposed to tie together what is disjointed in a child’s daily life into a semantic knot.     

The molecular genetics of bacteriophage: the work of Norton Zinder

In 1966, Norton Zinder and Joshua Lederberg discovered that Salmonella could exchange genes via bacteriophages. They named this phenomenon “genetic transduction.” This discovery set Zinder on a lifelong journey researching bacteriophage. In the two Journal of Biological Chemistry (JBC) Classic papers reprinted here, Zinder and Nina Fedoroff present their findings on the phage f2 replicase.Properties of the Phage f2 Replicase. I. Optimal Conditions for Replicase Activity and Analysis of the Polynucleotide Product Synthesized in Vitro (Fedoroff, N. V., and Zinder, N. D. (1972) J. Biol. Chem. 247, 4577–4585)Properties of the Phage f2 Replicase. II. Comparative Studies on the Ribonucleic Acid-dependent and Poly(C)-dependent Activities of the Replicase (Fedoroff, N. V., and Zinder, N. D. (1972) J. Biol. Chem. 247, 4586–4592)Norton David Zinder was born in New York City in 1928. He attended the prestigious Bronx High School of Science and went on to Columbia University where he received his B.A. in biology in 1947. Zinder then joined the graduate program at the University of Wisconsin-Madison, studying under geneticist Joshua Lederberg.Open in a separate windowNorton ZinderLederberg recently had found that Escherichia coli could mate and exchange genes (conjugation), a discovery for which he would be awarded the 1958 Nobel Prize in Physiology or Medicine. Zinder''s assignment was to continue Lederberg''s investigations using Salmonella. To do this, he needed to obtain large numbers of mutant bacteria. Rather than using the traditional method of exposing the Salmonella to mutagens and testing the survivors, Zinder decided to use a nutritionally deficient medium and penicillin (negative selection) to select for mutants (1). However, when he began investigating conjugation in Salmonella, most of his attempts at crossing the mutants failed. Fortunately, one mutant strain produced some prototrophs; but puzzlingly, Zinder''s markers did not segregate. Further experiments showed that the mutants were exchanging genes via bacteriophages (2). Lederberg and Zinder named this new phenomenon “genetic transduction.”Zinder received his M.S. in genetics in 1949 and completed his Ph.D. in medical microbiology in 1952. He then accepted a position as assistant professor at Rockefeller University (then known as Rockefeller Institute for Medical Research). By 1964 Zinder had become a full professor of genetics, and approximately 10 years later he was named John D. Rockefeller, Jr. Professor of Molecular Genetics. In 1993 Zinder was appointed dean of graduate and postgraduate studies.At Rockefeller, Zinder continued his studies of the molecular genetics of phages. He discovered the f2 phage, which was the first bacteriophage known to contain RNA as its genetic material, and demonstrated that RNA phage replication is not dependent on DNA (3).Zinder''s two Journal of Biological Chemistry (JBC) Classics reprinted here look at the phage f2 replicase. In the first paper, Zinder and his graduate student Nina V. Fedoroff show that the enzyme, purified on the basis of its poly(G) polymerase activity, could carry out the in vivo synthetic reactions involved in phage RNA replication. They also report that phage replicase activity is stimulated by salt and by a brief preliminary incubation at high ionic strength. The second paper, also by Zinder and Fedoroff and printed back-to-back with the first, compares the f2 poly(G) polymerase and replicase activities under a variety of conditions. They examined the effects of ionic strength, temperature, magnesium ion concentration, and template and substrate concentrations on the enzymes'' activities. Based on their results, Zinder and Fedoroff suggest a distinction between initiation and polymerization sites on the enzyme complex.Zinder remains at Rockefeller as John D. Rockefeller, Jr. Emeritus Professor and continues to research bacteriophage. Currently he is using genetics, biochemistry, and molecular biology to analyze the filamentous bacterial virus, f1, and its interactions with its host, Escherichia coli. His other studies relate to protein-DNA recognition, membrane anchoring, and questions of protein structure.In recognition of his many contributions to science, Zinder has received numerous honors and awards. These include the 1962 Eli Lilly Award in Microbiology and Immunology from the American Society of Microbiology, the 1966 Award in Molecular Biology from the National Academy of Sciences, the 1969 Medal of Excellence from Columbia University, and the 1982 Award for Scientific Freedom and Responsibility from the American Association for the Advancement of Science. Zinder became a member of the American Academy of Arts and Sciences in 1968 and of the National Academy of Sciences in 1969.Zinder''s coauthor on the two JBC papers also has gone on to a distinguished career in science. Fedoroff received her Ph.D. in 1972 and was a staff scientist at the Carnegie Institution of Washington. She joined the faculty of the Pennsylvania State University in 1995 and became the Evan Pugh Professor, Penn State''s highest academic honor, in 2002. She currently holds the Verne M. Willaman Chair of Life Sciences. In 2007, U. S. Secretary of State Condoleezza Rice named Fedoroff her science and technology adviser. She remains in this position today, serving U. S. Secretary of State Hillary Clinton. Fedoroff is a 2006 National Medal of Science laureate and a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the Phi Beta Kappa and Sigma Xi honor societies. Her current research focuses on the mechanisms that allow plants to withstand the environmental challenges of a changing climate.     

All human monocytes have the capability of expressing HLA-DQ and HLA-DP molecules upon stimulation with interferon-gamma

We have simultaneously studied expression of all three classes of human Ia (HLA-DR, DP, and DQ) on normal human B cells and monocytes (M phi) by using two-color immunofluorescence and flow cytometry. Expression was investigated on freshly isolated cells and after incubation of cells for 48 and 96 hr in interferon-gamma (IFN-gamma). All freshly isolated B cells express high levels of DR, DQ, and DP, and these levels are unchanged by incubation with IFN-gamma for 48 hr and 96 hr. In contrast, freshly isolated M phi are on the average 91% DR+, 32% DQ+, and 15% DP+. Incubation with IFN-gamma increases Ia expression on M phi to 98% DR+, 75% DQ+, and 58% DP+ at 48 hr, with virtually all cells becoming positive for all three Ia antigens at 96 hr. Furthermore, after the 96-hr incubation, antigen density increases 10-fold for DR, 15-fold for DQ, and 15-fold for DP in M phi to reach levels of expression comparable with B cells. These studies demonstrate that all peripheral blood monocytes have the capacity to become HLA-DQ and HLA-DP positive; IFN-gamma regulates expression of all three classes of human Ia in M phi; and IFN-gamma does not significantly modulate Ia expression in B cells.     

IgM induction in murine B hybridomas with Ia-restricted T cell clones: a monoclonal model for T and B cell interactions in antibody response

The mechanism of MHC-restricted T and B cell interactions in antibody response was studied with IgM-inducible B hybridomas and antigen-specific helper T cell clones. B hybridomas were prepared by fusion between splenic B cells from (CBA/N (H-2k) X BALB/c (H-2d)) F1 (NBF1) male mice and a B lymphoma cell line, M12.4.5. A B hybridoma clone, 1M70, which expressed I-Ad but not I-Ak determinants was chosen in the present study. IgM secretion was induced in 1M70 when it was cocultured with a "resting" KLH-specific and H-2d restricted helper T cell clone in the presence of KLH. A "resting" KLH-specific and H-2k restricted T cell clone did not induce IgM secretion in 1M70 even in the presence of KLH. However, when these KLH-specific T cell clones were activated by KLH and appropriate antigen presenting cells, both H-2d and H-2k restricted T cell clones induced IgM secretion in 1M70 even in the absence of KLH. A monoclonal anti-I-Ad antibody inhibited IgM secretion induced by a "resting" H-2d restricted T cell clone, but not by an "activated" T cell clone. These results indicated that T cell clones recognized antigens in the context of Ia molecules on B hybridomas in a MHC-restricted manner and were activated to produce B cell stimulatory factors which in turn acted on B hybridomas in a non-MHC-restricted manner and induced differentiation of B hybridomas into IgM secreting cells.     

Amyloid Cardiomyopathy in Hereditary Transthyretin V30M Amyloidosis - Impact of Sex and Amyloid Fibril Composition

Purpose

Transthyretin V30M (ATTR V30M) amyloidosis is a phenotypically diverse disease with symptoms ranging from predominant neuropathy to exclusive cardiac manifestations. The aims of this study were to determine the dispersion of the two types of fibrils found in Swedish ATTR V30M patients -Type A consisting of a mixture of truncated and full length ATTR fibrils and type B fibrils consisting of full length fibrils, and to estimate the severity of cardiac dysfunction in relation to fibril composition and sex.

Material and Methods

Echocardiographic data were analysed in 107 Swedish ATTR V30M patients with their fibril composition determined as either type A or type B. Measurements of left ventricular (LV) dimensions and evaluation of systolic and diastolic function including speckle tracking derived strain were performed. Patients were grouped according to fibril type and sex. Multivariate linear regression was utilised to determine factors of significant impact on LV thickness.

Results

There was no significant difference in proportions of the two types of fibrils between men and women. In patients with type A fibrils, women had significantly lower median septal (p = 0.007) and posterior wall thicknesses (p = 0.010), lower median LV mass indexed to height (p = 0.008), and higher septal strain (p = 0.037), as compared to males. These differences were not apparent in patients with type B fibrils. Multiple linear regression analysis revealed that fibril type, sex and age all had significant impact on LV septal thickness.

Conclusion

This study demonstrates a clear difference between sexes in the severity of amyloid heart disease in ATTR V30M amyloidosis patients. Even though type A fibrils were associated with more advanced amyloid heart disease compared to type B, women with type A fibrils generally developed less cardiac infiltration than men. The differences may explain the better outcome for liver transplanted late-onset female patients compared to males.     

Secondary mouse mixed lymphocyte reaction (MLR) in vitro: Correlation between primed cells reactivity and serological typing for Ia specificities

B10.M (H-2^f) spleen lymphocytes were cultured for 14 days with X-irradiated B10.P (H-2 ^p ) lymphocytes. These primed cells were then tested for their capacity to respond to a secondary stimulation induced by a panel of mouse cells carrying differentH-2 haplotypes. The third-party cells induced various degrees of proliferation which could be expressed as a percentage of the proliferation induced by the primary stimulating strain (relative response = RR) and could then be classified according to the RR. Anti-Ia antibodies present in a B10.M anti-B10.P serum were studied by the dye exclusion lymphocytotoxicity technique (LCT) against the same panel, after absorption of H-2K, D antibodies on B10.P platelets. The strain panel could then be classified according to the LCT titers of the absorbed immune serum. A significant correlation (r=0.96,P<0.01) was found between both classifications. According to the Ia chart, the public specificities involved were Ia.6, 7, and 13, but these did not fully explain either the primed cell reactivity or the LCT results. An unexpected crossreactivity was observed between B10.P and B10. Absorption-elution experiments with A.TH anti-A.TL serum demonstrated that B10 and B10.P share the Ia.3 antigen. These results indicate that the structure(s) recognized by the primed lymphocytes is the Ia antigen(s).Abbreviations used in this paper RR Relative response - LCT Dye exclusion lymphocytotoxicity technique - MLR Mixed lymphocyte reaction - PC Primed cell - MHC Major histocompatibility complex - PLT Primed lymphocytes typing test     

Modulation of mouse peritoneal macrophage Ia and human peritoneal macrophage HLA-DR expression by alpha 2-macroglobulin "fast" forms

alpha 2-Macroglobulin (alpha 2M) is converted from its native form into electrophoretically "fast" forms by reaction with proteinases or with methylamine. The "fast" forms both bind to specific receptors on macrophages (MP). We have previously shown that alpha 2M "fast" forms modulate effector functions of murine peritoneal MP. In the present study, alpha 2M "fast" forms antagonized the increase in MP HLA-DR and Ia expression induced in vitro by interferon-gamma (IFN-gamma). This effect was observed with human peritoneal MP, as well as MP from peptone-injected and bacillus Calmette-Guérin-infected mice of three strains. alpha 2M-trypsin, which had been reacted with aprotinin and alpha 2M-methylamine, both of which lack proteolytic activity, also antagonized interferon-induced Ia expression. alpha 2M "fast" forms also reduced the ability of MP to serve as accessory cells for lectin-induced lymphocyte proliferation. alpha 2M "fast" form is an immune modulator of human and murine MP function, probably through a specific receptor-mediated mechanism.     

The modulation of membrane Ia on human B lymphocytes

Using flow cytometry techniques, changes in surface Ia (DR and DS) expression on human B lymphocytes were correlated with changes in the cell cycle following stimulation with anti-mu. The effect of interleukin (IL)-1, IL-2, B-cell growth factor (BCGF), and interferons on Ia expression on resting B cells was also examined. A population of resting B lymphocytes was cultured in vitro with 100 micrograms/ml of anti-mu and immunofluorescently stained for DR and DS at various times following stimulation. Detectable increases in DR and DS expression were found within 8 hr, and the major increases (twofold and fourfold) in DR and DS expression occurred over the next 48 hr. Using cell cycle inhibitors and propidium iodide staining, it was demonstrated that the enhanced DR and DS expression following anti-mu stimulation began during G0 to G1 transition and increased as the cells progressed through G1 phase. During S and G2/M phases, there were minimal further increases in surface Ia. Although prolonged exposure of B cells to anti-mu was required for cellular activation, cell size enlargement, and progression into S phase, a brief exposure to anti-mu, insufficient for cellular activation, markedly enhanced Ia expression. Thus anti-mu-stimulated resting human B lymphocytes rapidly increase their surface Ia expression. This increase occurs predominantly prior to entrance into S phase and can occur in the absence of significant cellular activation. Interferons have been reported to modulate surface Ia expression on a human lymphoid cell line and on monocytes and supernatants with BCGF activity to enhance surface Ia expression on murine B cells; however, neither alpha-interferon, gamma-interferon, IL-1, IL-2, nor BCGF modified surface DR expression on normal resting human B cells.