bluuebunny/crossref_metadata_2025 huggingface dataset:
A phosphatidylethanolamine-containing complex on human B cells that mediates rosette formation with mouse erythrocytes.
Authors: Zalewski P D , Valente L , Forbes I J
Published: December 2022

The maturation-associated human B cell rosette receptor (MER) for mouse erythrocytes has been solubilized from B cells by mild trypsinization. It specifically agglutinates mouse red cells. Material with hemagglutinating activity partitioned into the lipid-soluble phase of a Folch partition of the trypsin extract was sensitive to phospholipase C and alkali, and on two-dimensional thin layer chromatography, it co-migrated principally with phosphatidylethanolamine (PE). Phosphatidylcholine, the major lipid present, was inactive. The relationship of phospholipid structure to hemagglutinating activity has been described. PE in the crude trypsin extract was associated with unidentified glycoprotein and albumin. Material containing hemagglutinating lipid bound to a wheat germ lectin-Sepharose column and was released by N-acetylglucosamine, indicating that the PE was complexed with glycoprotein. When the crude trypsin extract or eluate from the lectin column was extracted with aqueous phenol, hemagglutinin in the aqueous phase no longer bound to wheat germ lectin-Sepharose; however, albumin was greatly enriched, indicating that some of the PE exists in a complex with albumin. The molar ratio of PE to albumin was approximately 200:1. After delipidation, this albumin (in molar excess) inhibited hemagglutination by PE in the same way as a recently described subclass of serum albumin. Studies with phospholipase-treated B cells were also consistent with PE being the MER. We conclude that MER is PE, existing in a complex containing glycoprotein and a subclass of albumin. The capacity to form rosettes can be transferred to nonrosetting Raji B cells by the complex, but not pure PE, indicating that the proteins may be involved in orienting PE correctly for it to function as the MER.
Circulating cellfree Fc gamma 2b/gamma 1 receptor in normal mouse serum: its detection and specificity.
Authors: Khayat D , Dux Z , Anavi R , Shlomo Y , Witz I P , Ran M
Published: December 2022

By using intact or Fab fragments of rat monoclonal antibodies against murine Fc gamma 2b/gamma 1 receptor, in a solid phase radioimmunoassay, we demonstrated the occurrence of circulating cellfree Fc gamma 2b/gamma 1 receptors (Cf-Fc gamma 2b/gamma 1R) in normal mouse serum. These Cf-Fc gamma 2b/gamma 1R were removed from serum by affinity chromatography by using Sepharose columns coupled with IgG but not by Sepharose coupled with F(ab')2 fragments. Furthermore, the material retained by and eluted from the Sepharose IgG column reacted with the monoclonal antibody; these results support a direct relationship between the antigenic and the functional Cf-Fc gamma 2b/gamma 1R that were detected in serum. This Cf-Fc gamma 2b/gamma 1R was found in all the 39 normal mouse sera that were tested. The results seemed to indicate that aging may be associated with increased levels of Cf-Fc gamma 2b/gamma 1R and that levels of circulating Fc gamma R may be under genetic regulation. By forming complexes with circulating IgG within the blood stream, such Cf-Fc gamma 2b/gamma 1R may modulate some of the functions in which the Fc portion of Ig is involved.
Purification and characterization of Rana pipiens brain Thy-1 glycoprotein.
Authors: Mansour M H , Cooper E L
Published: December 2022

The occurrence of Thy-1 antigens in Rana brain has been studied by the use of heterologous anti-Rana brain antisera raised in rabbit and BALB/c mouse (Thy-1.2) and AKR/J mouse (Thy-1.1) strains and by monoclonal anti-mouse Thy-1.1 and anti-mouse Thy-1.2 antibodies with the use of quantitative absorption assays. Three antigenic determinants were defined on Rana brain and referred to as: 1) the Rana-specific xenoantigen, 2) the Rana-mouse cross-reacting xenoantigen, and 3) the Thy-1.1 antigen. Thy-1 antigenic activities were solubilized from crude brain membranes in deoxycholate and followed by measuring the Rana-specific and the Thy-1.1 antigenic determinants. After solubilization, Rana brain Thy-1 antigens were purified by lentil lectin affinity chromatography and gel filtration on Sephadex G-200. A 605-fold and 400-fold enrichment in the Rana-specific and the Thy-1.1 antigenic activities with a yield of 25% and 17%, respectively, were obtained. Both antigenic activities were associated with a single glycoprotein of molecular size 3.1 nm and m.w. estimated at 27,000 by SDS-polyacrylamide gel electrophoresis. The serologic and biochemical properties of our purified Rana brain Thy-1 glycoprotein were very similar to those of the mammalian Thy-1 molecule, suggesting the conservation of the gene coding for Thy-1 during vertebrate evolution.
Effect of influenza virus infection on allergic sensitization to aerosolized ovalbumin in mice.
Authors: Sakamoto M , Ida S , Takishima T
Published: December 2022

An IgE antibody specific to ovalbumin was produced when C3H mice were first infected with influenza A virus before challenge with the aerosolized antigen. No antibody could be detected in those animals without preceding viral infection. Antigen inhalation immediately after virus infection could not induce the IgE antibody. A time lag of at least 2 days was required to sensitize the infected mice with inhaled antigen. The study revealed that allergic sensitization could be elicited only during the acute stage of the infection, but not in the convalescent stage. We concluded therefore that the inflammation of respiratory mucous membrane might allow inhaled antigens to penetrate the barrier, resulting in reaginic antibody production that has the capacity to serve as an allergic response.
Antigenic modulation induced by monoclonal antibodies: antibodies to measles virus hemagglutinin alters expression of other viral polypeptides in infected cells.
Authors: Fujinami R S , Norrby E , Oldstone M B
Published: December 2022

Polyclonal antibody to measles virus can have profound effects on external (outer plasma membrane) as well as internal (cytoplasmic) viral polypeptides expressed in infected cells. The process, termed "antibody-induced antigenic modulation," was further investigated by using monoclonal antibody to several viral polypeptides. Four monoclonal antibodies against the viral hemagglutinin had the ability to decrease the expression of the phosphoprotein, fusion, and membrane protein. A monoclonal antibody to the nucleocapsid protein did not cause these changes. The observed decreases were not due to preferential degradation of viral polypeptides as determined by pulse-chase experiments. Our results indicate that a specific signal to an epitope on the plasma membrane (monoclonal antibody measles virus hemagglutinin) can alter the expression of measles virus phosphoprotein and membrane protein, both polypeptides present in the cytoplasm of infected cells.
Neoplastic cells obtained from Hodgkin's disease function as accessory cells for mitogen-induced human T cell proliferative responses.
Authors: Fisher R I , Bates S E , Bostick-Bruton F , Tuteja N , Diehl V
Published: December 2022

Purified human peripheral blood T cells that have been depleted of Ia-bearing cells and adherent cells do not proliferate in response to concanavalin A. The addition of as few as 1% radiated L428 tumor cells restores the proliferative capacity of the T cells. The L428 cell line is a long-term tissue culture line of Reed-Sternberg cells obtained from a patient with Hodgkin's disease. The proliferation of the T cells plus the L428 cells follows the same kinetics and has the same response to varying doses of mitogen as either unfractionated mononuclear leukocytes or purified T cells plus allogeneic adherent cells. The L428 cells are 30 times more potent as accessory cells than allogeneic adherent cells. The accessory cell function of the L428 cells is not blocked in cultures containing anti-Ia antibody. Neither supernatant from the L428 cell cultures nor human IL 1 replaces the accessory cells. The ability of the L428 cells to restore the proliferative capacity of purified T cells isolated from patients with active Hodgkin's disease was also studied. Patients with early stages of the disease had normal proliferative responses in the presence of the L428 accessory cells. However, the proliferative response of the poor prognosis, advanced-stage patients was reduced as compared to age- and sex-matched controls, supporting a deficit in their T cell function. The L428 tumor cells share many properties such as accessory cell function, morphology, and cell surface markers with the dendritic cells described in animal and human systems.
Antigen-stimulated human B cell clones are committed to the production of a single class of antibody in vitro.
Authors: Yarchoan R , Engler R J , Barrow L A , Kurman C C , Nelson D L
Published: December 2022

We have investigated the isotype(s) of antibody produced in vitro by antigen-stimulated human B cell clones. An analysis of the class(es) of antibody produced in multiple replicate cultures containing a mean of less than one precursor B cell per well was consistent with the hypothesis that individual B cell precursors produced a single class of antibody. This result was obtained by using cells isolated from either the peripheral blood or tonsils. Thus, under the culture conditions utilized, no intraclonal isotype switching was detected.
Demonstration of activation-specific interactions among B lymphocyte membrane proteins by a photoreactive cross-linking agent.
Authors: Wolfert R L , Goodman M G , Weigle W O
Published: December 2022

The formation of plasma membrane protein complexes during B cell activation was examined by covalently stabilizing these complexes with a photolabile, cleavable, cross-linking reagent, dithiobisphenylazide (DTPA). Analysis by SDS polyacrylamide gel electrophoresis indicates that LPS induces a time-dependent rearrangement in membrane proteins of splenic B cells. These rearrangements were localized to the plasma membrane by examination of surface-labeled detergent lysates and purified plasma membrane preparations. DTPA-stabilized rearrangements could be detected as early as 15 min and were stable between 3 and 24 hr after mitogen addition. These changes are consistent with the formation of different functional protein complexes during B cell activation. LPS does not induce membrane protein rearrangement in thymocytes, nor does Con A do so in B cells. Therefore, the changes appear to be correlated with the transmission of a relevant activation signal. Activation of B cells with 8- bromoguanosine ( 8BrGuo ), an intracellular mitogen, did not result in protein rearrangement until 12 hr after mitogen addition, suggesting that initial stages of signal transduction by 8BrGuo and LPS follow separate pathways. A common "activated state" of the membrane is established by 12 hr. Inhibition of de novo protein synthesis by cycloheximide did not interfere with formation of new protein complexes during early stages of activation (15 min and 3 hr). These data indicate that covalent cross-linking with DTPA can be used to demonstrate activation-specific interactions among proteins on the surface membrane of B cells.
Anti-idiotype stimulation of antigen-specific antigen-independent antibody responses in vitro. II. Triggering of B lymphocytes by idiotype plus anti-idiotype in the absence of T lymphocytes.
Authors: Shenk R R , Weissberger H Z , Dickler H B
Published: December 2022

Antibodies specific for the idiotypes of B10 anti-(T,G)-A--L antibodies (anti-id) induced B lymphocytes to secrete anti-(T,G)-A--L antibodies in vitro in the absence of both antigen and T lymphocytes, provided either that the B lymphocytes were previously primed in vivo with (T,G)-A--L or that id specific for (T,G)-A--L was added to the cultures. These antigen- and T lymphocyte-independent responses were antigen specific and appeared not to require accessory cells. The results suggested that B lymphocyte activation occurred via the formation of id-anti-id complexes, and evidence was obtained that this activation involved two separate interactions between the B lymphocytes and the id-anti-id complexes. These studies document a previously undescribed regulatory function of anti-idiotype antibodies.
A population of resting IgM-IgD double-bearing lymphocytes in Peyer's patches: the major precursor cells for IgA plasma cells in the gut lamina propria.
Authors: Tseng J
Published: December 2022

The precursor cells in Peyer's patches and mesenteric lymph nodes responsible for repopulating IgA plasma cells in the gut lamina propria were identified by using cell separation and by using cell transfer in Ig allotype congeneic mice (CB-20 and BALB/cJ mice). It was found that the IgA precursor cells are mainly resting lymphoid cells bearing IgM and IgD on their surface. The IgA-bearing cells are also precursors; their repopulation efficiency, however, is remarkably low. The majority of the IgA precursor cells also bear complement receptors on their surface; this suggests that they are relatively mature B cells.
Cell-mediated cytotoxicity against allogeneic mutant H-2 antigens: restricted and nonrestricted responses.
Authors: Nakamura I
Published: December 2022

Two "gain and loss" type mutations of the H-2D region, the H- 2bm13 and H- 2bm14 , resulted in the expression of noncross-reactive CML determinants that are unique to each mutation, the Dbm13 gains and Dbm14 gains, respectively. According to the results of direct cytolytic and competitive inhibition assays of in vitro induced primary cytotoxic T lymphocytes, allogeneic responses specific for Dbm13 gains are generated by responders bearing the H-2b ( KbIbDb ) haplotype, but not by responders bearing the H- 2bm14 ( KbIbDbm14 ), KbIbDd , KbIbDk , or KbIb / qDq haplotype. Responses by the non-H-2b responders against Dbm13 are limited to those determinants shared by the Dbm13 and Db molecules. Because congenic mice differing only at the H-2D region are either responsive or nonresponsive to Dbm13 gains, the responsiveness is controlled by gene(s) in the H-2D region. F1 hybrid offspring of responsive (H-2b) and nonresponsive (non-H-2b) parents are invariably responsive, indicating genetic dominance of the responsiveness. In contrast to the response against Dbm13 gains, cytotoxicity specific for Dbm14 gains is generated by responders bearing the H-2b, H- 2bm13 , KbIbDd , KbIbDk , or KbIb / qDq haplotype. These data indicate the existence of two types of allogeneic MHC determinants; one, represented by Dbm14 gains, is the classic type capable of eliciting CML responses in mice of a wide range of H-2 haplotypes, whereas the other, exemplified by Dbm13 gains, elicits CTL responses only in mice of a few related haplotypes. It is proposed that recognition of Dbm13 gains is restricted by structures shared by Db and Dbm13 but missing from other D (or L, R, etc.) molecules, such as Dbm14 , Dd, Dk, and Dq. Availability of various restricting structures in self MHC molecules may thus influence the alloreactive CTL repertoire.
Virus-induced enhancement of lymphocyte-mediated antibody-dependent cytotoxicity (ADCC) in vitro.
Authors: Alsheikhly A R , Wåhlin B , Andersson T , Perlmann P
Published: December 2022

The effect of Parotis virus on antibody-dependent cellular cytotoxicity in vitro (ADCC) of human lymphocytes was investigated in a 51Cr-release assay and, at the effector cell level, in an ADCC plaque assay. Target cells were bovine or chicken erythrocytes, which are not susceptible to natural cytotoxicity (NK) of human lymphocytes. They were not killed when incubated with virus-treated lymphocytes in the absence of antibodies. Treatment of the lymphocytes or the target cells with small amounts of virus, however, resulted in a very significant enhancement of ADCC. The same results were obtained with live or UV-inactivated virus, suggesting that enhancement was a passive phenomenon not requiring infection. Enhancement was already significant after 3 hr of incubation, indicating that it was independent of endogenously released interferon. Enhancement of ADCC by virus was due to effector cell recruitment rather than due to the increase of the cytotoxic potential of the individual K cell. The highest frequency of effector cells was present in Percoll fractions enriched in large granular lymphocytes (LGL). Virus treatment resulted in recruitment of effector cells carrying T cell markers such as the T3 antigen (OKT3+), receptors for sheep erythrocytes, or Fc receptors for IgM. In contrast, the absolute number of K cells carrying the HNK-1 marker (Leu-7) or receptors for C3 fragments was not changed by the virus. It is concluded that Parotis virus enhances ADCC by improving effector cell-target cell contacts, resulting in recruitment of effector cells with T cell characteristics. Recruitment is accompanied by a significant reduction of the antibody concentration needed for ADCC induction. This virus-mediated enhancement of ADCC may be of importance for protection of the host in the early phases of a virus infection in which the amounts of anti-viral IgG antibodies capable of inducing cellular cytotoxicity may yet be very small.
Immunoglobulin synthesis after HLA-identical marrow grafting. V. The role of peripheral blood monocytes in the regulation of in vitro immunoglobulin secretion stimulated by pokeweed mitogen.
Authors: Shiobara S , Witherspoon R P , Lum L G , Storb R
Published: December 2022

The ability of purified monocytes to regulate in vitro immunoglobulin (Ig) production was examined in 12 patients after HLA-identical marrow grafting. Five patients were studied less than 3 mo after grafting and seven more than 1 yr after grafting. One of the former had acute graft-vs-host disease and five of the latter had chronic graft-vs-host disease. Ficoll-Hypaque-separated peripheral blood mononuclear cells from patients, normal marrow donors, or healthy unrelated individuals were separated into T and non-T cells by sheep erythrocyte rosetting. Highly enriched monocyte and B cell subpopulations were obtained by placing the non-T cells over discontinuous Percoll gradients. Co-cultures of patient or normal monocyte populations with either normal or patient T and B cells with pokeweed mitogen were performed. A hemolytic plaque assay was used to assess Ig secretion after 6 days of culture. Co-culture of T and non-T cells from 10 of 12 patients failed to produce Ig. Monocyte-enriched fractions from all patients provided normal accessory cell functions when co-cultured with normal T and B cells. Two of five patients with chronic graft-vs-host disease had monocytes that suppressed Ig synthesis at high ratios of monocytes to normal T and B cells. Normal monocyte-enriched fractions did not restore Ig production to T and B cells of patients whose T and non-T cells failed to produce Ig. These data indicate that the observed defects in pokeweed mitogen-driven Ig secretion after marrow grafting are due primarily to defective T and B cell functions and that the monocyte accessory function is intact in most patients studied.
Effects of diethyldithiocarbamate, an inhibitor of interferon antiviral activity, upon human natural killer cells.
Authors: Edwards B S , Merritt J A , Jelen P A , Borden E C
Published: December 2022

In support of a postulated role of the Cu++-dependent enzyme, superoxide dismutase (SOD), in antiviral effects of interferon (IFN), a close correspondence was previously shown to exist between inactivation of cellular SOD and concomitant blockade of IFN antiviral activity in fibroblasts by the Cu++-chelating agent, diethyldithiocarbamate (DDC). To further define the extent of "anti-IFN" activity, we initiated studies of DDC effects on IFN stimulation in the NK cell system. Unexpectedly, DDC directly inhibited cytotoxicity mediated by unstimulated NK cells. Pronounced inactivation occurred rapidly (less than 30 min), but was spontaneously reversible in the absence of DDC. Neither cell viability nor lymphocyte binding to target cells was detectably affected. Preincubation of DDC with Cu++ or Zn++ failed to neutralize its inhibitory effects nor could function be restored in DDC-pretreated NK cells by subsequent addition of Cu++, Zn++, Mg++, or Ca++. DDC treatment that inactivated NK cells did not detectably alter lymphocyte SOD activity. Thus, inhibition was probably not attributable to chelating properties of DDC. N-ethyl maleimide (NEM) and para-( hydroxymercuri ) benzoic acid ( PMBA ), enzyme inhibitors that preferentially react with sulfhydryl groups, both inactivated NK cells in a time- and dose-dependent manner similar to that of DDC. Preincubation with the sulfhydryl compound, cysteine, neutralized in parallel fashion the capacity of NEM, PMBA , and DDC to inhibit NK cell activity. Thus, a previously unreported reactivity of DDC with sulfhydryl groups appeared to be the basis of inhibition. NK cells incubated 1 hr with IFN and subsequently cultured 17 to 23 hr without IFN were activated to an extent comparable to cells continuously incubated 18 to 24 hr with IFN. Exposure to IFN for 1 hr was therefore sufficient to commit NK cells to acquisition of a fully activated state. Whether preactivated by a 1-hr or 18- to 24-hr IFN treatment, activated NK cells retained the DDC-sensitive phenotype characteristic of fresh unstimulated NK cells. Thus, prolonged IFN treatment did not render NK cells resistant to DDC or preferentially activate a DDC-sensitive NK cell subset. An 18- to 24-hr incubation of DDC-pretreated cells in the continual presence of IFN resulted in the boosting of NK cell activity. However, the 1-hr IFN pulse treatment protocol was consistently ineffective in boosting when IFN was added just after DDC-pretreatment. These results strongly suggested that DDC temporarily rendered NK cells unresponsive to what, under normal circumstances, approximated an optimally potentiating IFN stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)
Differentiation of NK-like cells from OKT3-, OKT11+, and OKM1+ small resting lymphocytes by culture with autologous T cell blasts and lymphokine.
Authors: Warren H S
Published: December 2022

NK-like cells have been generated in vitro from a resting lymphocyte population of PBMC by 8 days culture with mitomycin C-treated autologous T cell blasts and lymphokine. The responder lymphocyte population was purified to the extent that it lacked classical NK cells, and lacked the precursors of MLC-derived NK-like cells and of lymphokine-activated killer cells. The NK-like cells were not generated when the responder lymphocytes were cultured with either T cell blasts or lymphokine alone. Thus, at least two signals are required for their activation. Metabolically inactive T cell blasts plus lymphokine were effective in stimulating the generation of NK-like cells, suggesting that a membrane determinant on the T cell blasts was involved in activation. The phenotype of the NK-like cells and their precursors was analyzed by monoclonal antibody and complement treatment. The phenotype of both precursor and effector cells was OKT3-, OKT11+, and OKM1+, with a distinct pattern of reactivity with OKT8 and Leu-7 for each individual donor tested. The NK-like cells were morphologically large granular lymphocytes, and they killed a variety of target cells. These studies show that signals provided by autologous T cell blasts and lymphokine are essential in triggering the differentiation of NK-like cells from appropriately purified resting lymphocytes. This mechanism of activation could occur in vivo, leading to the generation of NK cells subsequent to an antigen-specific T cell response.
Homing of Lyt-2+ and Lyt-2- T cell subsets and B lymphocytes to the central nervous system of mice with acute experimental allergic encephalomyelitis.
Authors: Trotter J , Steinman L
Published: December 2022

Subpopulations of lymphoid cells were compared with respect to their ability to migrate into the central nervous system (CNS) of mice with acute experimental allergic encephalomyelitis (EAE). In mice with established lesions, the majority of cells homing to the CNS are not presensitized to CNS antigens. B cells had a much reduced capacity to migrate into the CNS of sick mice compared with T cells. However, T cells of both the Lyt-2+ and Lyt-2- subsets homed equally well to the CNS. The relative paucity of B cells in the lesions of EAE and multiple sclerosis may thus partly result from the limited ability of these cells to migrate into the CNS across the blood-brain endothelial barrier. The predominance of Lyt-2- T cells over Lyt-2+ cells in these CNS lesions is unlikely to result from such a difference in homing capacity, but may reflect the ratio of these two cell types in the blood or preferential in situ expansion of the Lyt-2- population.
Colony-stimulating factor (CSF-1): its enhancement of plasminogen activator production and inhibition of cell growth in a mouse macrophage cell line.
Authors: Chen B D , Lin H S
Published: December 2022

CSF-1 is a hemopoietic growth factor that specifically causes the proliferation and differentiation of mononuclear phagocytic cells. J774 cells are a monocyte precursor-like macrophage cell line. This transformed macrophage cell line exhibits specific 125I-CSF-I-binding activity similar to that of normal murine macrophages, although its survival and growth is independent of CSF-1. At 0 degrees C, saturation of binding sites was achieved at 240 pM 125I-CSF-1. At 37 degrees C, the bound 125I-CSF-1 was rapidly internalized and degraded by the target cells with a T1/2 of approximately 30 min; degradation was inhibited by the addition of NH4Cl. The addition of CSF-1 to cultures caused dose-dependent inhibition rather than stimulation of [3H]thymidine uptake by J774 cells. Whereas CSF-1 stimulated the clonal growth of normal mouse peritoneal exudate macrophages, it inhibited the clonal growth of J774 cells in agar cultures. Furthermore, CSF-1 exhibited a concentration-dependent enhancement of the production of plasminogen activator (PA) by J774 cells. The enhanced production of PA was detected 6 hr after the addition of CSF-1 and was inhibited by the simultaneous addition of the anti-inflammatory drug. It appears that the effects of CSF-1 on cell proliferation and PA production by CSF-1 receptor-bearing cells are mediated by distinct intracellular pathways albeit through the same receptor.
Detection of HSV-1-induced lymphokine production in human cells by a direct indicator cell addition assay.
Authors: Clouse K A , Bach F H , Orosz C G
Published: December 2022

These studies present an efficient and sensitive method for detection of T cell growth factor (TCGF) activity in human lymphocyte cultures and illustrate that T cell growth factors are associated with T lymphocyte-mediated anti-HSV-1 responses. Secretion of TCGF is induced after stimulation of human peripheral blood mononuclear cells ( PBMNC ) with herpes simplex virus type 1 (HSV-1). Lymphokine activity is detected in a simple, sensitive method by studying [3H]thymidine incorporation after the addition of murine CTLL -20 cells to cultures of gamma-irradiated (4000 R), virus-stimulated PBMNC . By using this assay, we find that PBMNC from seropositive but not seronegative individuals produce detectable TCGF activity in a dose-dependent manner after incubation with HSV-1. Maximum activity is detected between 24 to 48 hr of incubation and correlates with in vitro proliferation of nonirradiated PBMNC in response to the virus. In addition, gamma-irradiated (1000 to 3000 R) PBMNC , which are frequently used as a source of antigen-presenting cells (APC), can secrete TCGF after contact with HSV-1. Lymphokine production by the APC-containing population is eliminated by gamma-irradiation (5000 R); such APC can still present UV-inactivated HSV-1 to HSV-1-responsive lymphoblasts, indicating that lymphokine production by T cells residing in the APC population is not essential for antigen presentation.
Amino- and carboxy-terminal sequence of mouse J chain and analysis of tryptic peptides.
Authors: Elliott B W , Steiner L A
Published: December 2022

Mouse J chain was isolated from an IgM-producing hybridoma by gel filtration and ion-exchange chromatography. The sequence of the amino-terminal 25 residues was determined. At these positions, the results agree with the amino acid sequence deduced from the cDNA sequence determined previously by Koshland and co-workers and indicate that a leader sequence terminating in glycine is removed to form the mature J chain. Tryptic peptides of J chain were isolated by high pressure liquid chromatography and their amino acid compositions were compared with those expected from the cDNA sequence. The amino acid sequence of the carboxy-terminal peptide and a mixture of two other peptides was determined. The results were consistent with the cDNA sequence except that we found valine, not leucine, at position 67, and arginine, not glycine, at position 117. The presence of aspartic acid at the carboxy-terminus, as predicted from the cDNA, indicates that processing does not occur at this end of the polypeptide chain. Upon amino acid analysis, glucosamine was found in tryptic peptides 47-57 and 47-58. J chain was also cleaved at aspartylproline bonds with formic acid and the unfractionated digest was subjected to automated Edman degradation. The mixed sequence was consistent with the sequence deduced from the cDNA at positions 1 to 13, 28 to 40, 52 to 64, and 73 to 85. In conjunction with the results obtained previously by analysis of cDNA, these data show that mouse J chain is a polypeptide containing 137 amino acid residues, 93 of which are identical to residues in human J chain.
Effects of leukotrienes and f-Met-Leu-Phe on oxidative metabolism of neutrophils and eosinophils.
Authors: Palmblad J , Gyllenhammar H , Lindgren J A , Malmsten C L
Published: December 2022

We assessed the effects of several leukotrienes and of f-Met-Leu-Phe on oxygen consumption in neutrophils and on the initial burst of chemiluminescence (CL) in both neutrophils and eosinophils. It was found that f-Met-Leu-Phe initiated 2.6 times higher oxygen consumption in neutrophils than did leukotriene B4 (LTB4). f-Met-Leu-Phe also stimulated five to 10 times more CL from both types of granulocytes than LTB4, which was at least five times more potent than its omega-hydroxylated metabolite, 20-OH-LTB4, whereas the corresponding 20-COOH derivative was effective only in eosinophils. The double dioxygenation product 5(S), 12(S)- DHETE caused no CL. Neutrophils from patients with chronic granulomatous disease did not respond with CL to any of the agents. The peak of CL occurred 50 to 60 sec after the addition of fMLP, whereas the LTB4-associated peak occurred after 5 to 6 sec and then rapidly subsided. The treatment of cells with sodium azide to inhibit the myeloperoxidase system did not change the kinetics or the rapid decline of the LTB4-induced CL. The CL response to LTB4 could be inhibited to 85% by 0.5 microgram/ml of superoxide dismutase, to 72% by 200 mg/ml of catalase, and to 50% by 80 microM of mannitol. The corresponding figures for f-Met-Leu-Phe-induced CL were 80, 58, and 16%, suggesting that, although a substantial part of the CL appears to be due to superoxide ion production, other oxygen radicals are involved in luminol-enhanced CL production. Thus, in contrast to some previous reports that leukotrienes do not stimulate an oxidative metabolic response in granulocytes despite their potent activity as chemotactic factors, our studies show that leukotrienes are definite inducers of granulocyte oxidative metabolism.
Inhibition of the function of activated properdin by squid chondroitin sulfate E glycosaminoglycan and murine bone marrow-derived mast cell chondroitin sulfate E proteoglycan.
Authors: Wilson J G , Fearon D T , Stevens R L , Seno N , Austen K F
Published: December 2022

We compared the relative capacities of two over-sulfated glycosaminoglycans, heparin and chondroitin sulfate E, to alter the function of native properdin (nP) and activated properdin (aP) in the formation and stabilization of the amplification C3 convertase (C3b,Bb). Heparin was more active on a weight basis than chondroitin sulfate E in inhibiting the formation of C3b,Bb without or with nP, but had no influence on the decay of a pre-formed convertase, either unstabilized or stabilized with nP or aP. In contrast, chondroitin sulfate E was over 10-fold more active than heparin in preventing the formation of C3b,Bb in the presence of aP, and gave dose-related acceleration of decay of pre-formed C3b,Bb,aP but not of unstabilized or nP-stabilized pre-formed convertase. The inhibitory effect of both glycosaminoglycans on the formation of C3b,Bb in the presence of nP or aP was less when the number of C3b sites per target cell was increased. The preferential action of chondroitin sulfate E on the function of aP during the formation and decay of C3b,Bb,aP as compared to C3b,Bb,nP implies functional differences in the two forms of P even when they have been incorporated into C3b,Bb. The equal potency, when adjusted for uronic acid content, of chondroitin sulfate E proteoglycan isolated from the T cell-dependent, bone marrow-derived murine mast cell and of chondroitin sulfate E glycosaminoglycan from squid reveals that the linkage of the glycosaminoglycan to a peptide core does not diminish its regulatory action on the alternative complement pathway.
Uptake and nature of the intracellular binding of cyclosporin A in a murine thymoma cell line, BW5147.
Authors: Merker M M , Handschumacher R E
Published: December 2022

In a survey of malignant cell lines including a variety of leukemias and lymphomas, BW5147, a T lymphoma from the spontaneous virus-associated thymoma in AKR mice, was found to be the most sensitive to growth inhibition by cyclosporin A (Cs A). Inhibition of growth was cell cycle phase-independent and inhibition of macromolecular precursor uptake was relatively nonspecific. Uptake of radiolabeled Cs A by these cells was characterized by two components: one that appeared saturable at low drug concentrations (0.03 to 1.0 microgram/ml), and another that was nonsaturable at higher drug concentrations (1.0 microgram/ml or higher). Most of the drug concentrated by cells (70 to 80%) was located in the cytosol (100,000 X G supernatant of lysed cells). The apparent m.w. of the drug-macromolecule complex was 15,000 to 20,000 as determined by m.w. exclusion columns. This complex could also be formed by adding drug to cytosol prepared from unexposed cells. The low m.w. complex migrated on a preparative isoelectric focusing column to form two peaks with isoelectric points of 6.8 and 8.5. A method was developed to assay for the binding component, and a sequence of m.w. exclusion columns and isoelectric focusing was used to effect partial purification of the Cs A binding component.
Streptococcal Fc receptors. I. Isolation and partial characterization of the receptor from a group C streptococcus.
Authors: Reis K J , Ayoub E M , Boyle M D
Published: December 2022

A receptor for the Fc region of immunoglobulin G was extracted from a group C streptococcus, purified and physicochemically characterized. The Fc receptor was extracted in high yield by lysis of the bacteria after infection with bacteriophage. The soluble receptor was purified to functional homogeneity by sequential chromatography on cellulose phosphate, DEAE, and selective elution from a column of immobilized human IgG. Four hundred micrograms of the functionally pure protein was obtained per gram (wet weight) of bacteria extracted. The affinity-purified receptor was functionally homogeneous in binding to the Fc region of human IgG; however, the product was heterogeneous on both non-denaturing and SDS polyacrylamide gels. Four major protein bands were observed, with the predominant form of the Fc receptor having an m.w. of 64,000 daltons. Antibody prepared against the major Fc receptor protein ( FcRc -II) was capable of reacting with all the fractions and completely inhibiting functional activity. The results of the competitive binding studies suggest that the purified Fc receptor behaves as a single receptor, and that the differences in charge and size were probably due to covalently bound cell wall constituents.
Quantitative differences in the expression of a 72,000 molecular weight cell surface glycoprotein (GP72) in Trypanosoma cruzi zymodemes.
Authors: Chapman M D , Snary D , Miles M A
Published: December 2022

A high affinity monoclonal antibody, 8G2 B9, was used to assess the expression of a 72,000 m.w. glycoprotein ( GP72 ) in isoenzyme-typed T. cruzi strains ( zymodemes ). Western blotting analysis of T. cruzi clones showed that 8G2 B9 bound strongly to GP72 and also suggested that this antigen was absent or weakly detectable in T. cruzi zymodeme 1 (Z1) strains. Purified 8G2 B9 was radiolabeled with 125I and used in an inhibition radioimmune binding assay to compare the quantities of GP72 in different zymodemes . Ninety-six T. cruzi strains were assayed, of which 36 were Z1, 36 were Z2, five were Z3 , and 19 were Z2 (heterozygous). Most (64%) Z1 strains lacked detectable GP72 , whereas this antigen was always detected Z2 and Z2 (heterozygous) strains. There was an 18-fold difference between geometric mean values for the quantities of GP72 (expressed as nanograms per milligram total cell protein) in Z1 and Z2 strains (Z1, 36 ng/mg; Z2, 639 ng/mg; p less than 0.001). There were also significant differences between the geometric mean values for Z2 and Z2 (heterozygous) strains, i.e., 639 ng/mg and 1648 ng/mg, respectively (p less than 0.001). GP72 was detected in four of the Z3 strains in quantities ranging from 740 to 3640 ng/mg. The absolute amounts of antigen in GP72 -positive strains were low, comprising less than 1% of the total cell protein. The specificities of two other anti- GP72 monoclonal antibodies, 7C6 D7 and WIC 29.26, were compared with 8G2 B9. Both antibodies completely inhibited the binding of 8G2 B9 to GP72 in solid phase immunoassays, suggesting that they reacted with the same antigenic determinants. The results show that monoclonal antibody-based assessments of the expression of GP72 correlate with zymodeme classification, and they also suggest that the monoclonal antibodies recognize major antigenic determinants on GP72 . It should be possible to use 8G2 B9 as an immunologic marker to additionally investigate the clinical significance of T. cruzi zymodemes and the biologic significance of GP72 .
Purification and properties of cytoplasmic granules from cytotoxic rat LGL tumors.
Authors: Millard P J , Henkart M P , Reynolds C W , Henkart P A
Published: December 2022

To evaluate the role of NK cell granules in the lytic activity of NK cells, cytoplasmic granules of rat NK tumors were purified by centrifugation of the cell homogenates in a Percoll gradient. Analysis of such gradients showed a band of light-scattering material near the bottom of the tube; assay of gradient fractions for lytic activity against SRBC showed a potent lytic activity giving a sharp peak in this region. Complete lysis of SRBC was achieved with less than 1 microgram/ml protein of the most active fractions. Examination in the electron microscope showed that a pool of fractions containing lytic activity consisted of pure cytoplasmic granules showing similar morphology to those found in the LGL tumors. The lytic band was associated with a peak in the activity of four different lysosomal enzymes. Analysis of Percoll gradient fractions showed that marker enzymes for mitochondria, plasma membrane, and cytosol were well separated from this activity peak. Analysis of the Percoll gradient fractions by SDS gel electrophoresis showed that this granule fraction was free of contamination of proteins from other parts of the gradient. The granules contained major protein bands of 62, 58, 30, 29, and 28 kilodaltons. In addition to protein, the purified granule fractions contain hexose and uronic acid, but no nucleic acids or phospholipids were detected in chemical assays. Major amounts of chymotryptic, tryptic, and elastase activities were not present, nor were peroxidase or lysozyme activities detectable in substantial amounts. These data show that NK tumor cell cytoplasmic granules contain a potent lytic activity and have biochemical properties that distinguish them from granules present in granulocytes and mast cells.
Phenotypic heterogeneity of antisyngeneic tumor killer cells (ASTK) generated in allogeneic mixed lymphocyte reactions.
Authors: Macphail S , Paciucci P A , Stutman O
Published: December 2022

By using monoclonal antibodies to Thy-1, Lyt-2, and Qa-5 differentiation antigens, we demonstrated a heterogeneity of cytotoxic cells developed in allogeneic mixed lymphocyte responses that lyse tumor cells syngeneic with the responder cells. There are minimally two Thy-1+ populations, one of which is Lyt-2+ and the other Lyt-2-. There is probably also a Thy-1- population. Most of the Lyt-2- tumor killer cells are Qa-5+, and most of the Lyt-2+ tumor killer cells are Qa-5-.
Human T lymphocyte activation by monoclonal antibodies; OKT3, but not UCHT1, triggers mitogenesis via an interleukin 2-dependent mechanism.
Authors: Van Wauwe J P , Goossens J G , Beverley P C
Published: December 2022

OKT3 and UCHT1 monoclonal antibodies, which recognize the same human T cell surface antigen, induce proliferation in T lymphocytes. In this report, we compared the mechanism by which these antibodies trigger DNA synthesis in human peripheral blood mononuclear cell (PBMC) cultures. Whereas PBMC from all donors tested were mitogenically inducible by OKT3, cells from only 25 of 40 donors were responsive to UCHT1 . UCHT1 treatment of PBMC from responders, but not from nonresponders, resulted in the expression by T cells of membrane binding sites reactive with anti-Tac monoclonal antibody, which specifies the human interleukin 2 (IL 2) receptor. UCHT1 -induced PBMC supernatants from nonresponders, but unexpectedly, also from responders, contained no measurable IL 2 activity. In keeping with this finding, anti-Tac monoclonal antibody failed to suppress UCHT1 -triggered [3H]thymidine incorporation into PBMC from responsive donors. By contrast, OKT3 treatment of PBMC from all donors led to the emergence of IL 2 receptors, and substantial IL 2 production, and the resultant DNA synthesis was inhibitable by anti-Tac antibody. These data indicate that the interaction of OKT3 and UCHT1 monoclonal antibodies with the same T cell structure leads to the induction of proliferation via two different mechanisms: one dependent on the availability of IL 2 (OKT3) and one independent on the production and processing of this lymphokine ( UCHT1 ). PBMC unresponsiveness to UCHT1 could therefore not be related to a dysfunction in IL 2 synthesis or IL 2 receptor display.
The Fc portion of intact IgG blocks stimulation of human PBMC by anti-T3.
Authors: Looney R J , Abraham G N
Published: December 2022

The means by which normal human serum inhibits the activation of PBMC by OKT3 has been investigated. The Fc portion of intact IgG is shown to be the major inhibitor in human serum of this OKT3-induced stimulation. Furthermore, inhibition by IgG subclasses correlated with their ability to bind to the monocyte Fc receptor, i.e., IgG1 and IgG3 produced greater inhibition than IgG2 and IgG4, and this inhibition was competitive. In contrast, hypogammaglobulinemic serum, IgA, IgM, and F(ab')2 of IgG were not inhibitory relative to intact IgG or Fc of IgG. Because of the similarities between T3 and the idiotype-defined T cell receptor for antigen, these investigations suggest that IgG might modulate the interactions between the T cell recognition complex and anti-idiotype antibody, thus regulating the idiotype network.
In vitro human lymphocyte responses to Cryptococcus neoformans. Evidence for primary and secondary responses in normals and infected subjects.
Authors: Miller G P , Puck J
Published: December 2022

Cryptococcus neoformans causes meningitis and disseminated infection in healthy individuals, but more commonly in hosts with defective immune responses. To study the role of immune lymphocytes in protection and recovery from this infection, in vitro lymphocyte proliferative responses to whole killed organisms were characterized in normal controls and in patients with cryptococcosis. Several differences were found between these two groups. All normal individuals were found to have significant proliferative responses to cryptococci in vitro; however, patients recovering from infection had accelerated and augmented responses. Patients' T cells, but not control T cells, were found to produce interleukin 2 (IL 2) during initial stimulation in vitro. After in vitro priming, mononuclear cells from normal controls rechallenged with cryptococci in vitro demonstrated accelerated kinetics and IL 2 production similar to that of cells from recovering patients. Proliferative responses in normals required T cells and antigen-presenting cells, and resulted in an increase in the proportion of T8+ and Tac+ cells in the responding population by the ninth day of primary stimulation. An increase in Tac+ cells, but not T8+ cells, was found by the fourth day of secondary stimulation. These results demonstrate in vivo acquisition of T cell responsiveness to the organism in this small group of recovering patients, and in vitro acquisition of T cell recognition of this antigen by normal T cells during primary stimulation. The data suggest that these responses represent in vitro priming to cryptococci and indicate a role for the T8+ lymphocyte subpopulation, both unusual findings for previously described in vitro responses to soluble antigens.
The Fc receptor for IgG on human natural killer cells: phenotypic, functional, and comparative studies with monoclonal antibodies.
Authors: Perussia B , Trinchieri G , Jackson A , Warner N L , Faust J , Rumpold H , Kraft D , Lanier L L
Published: December 2022

We compare five monoclonal antibodies ( B73 .1, 3G8 , Leu- 11a , Leu- 11b , and VEP13 ) that react with natural killer (NK) cells and polymorphonuclear cells (PMN). We show that all of these antibodies are directed against and inhibit the functional properties of the receptor for the Fc portion of IgG (FcR). Modulation of the FcR on NK cells after reaction with immune complexes induces the disappearance of the antigen(s) recognized by each of the five antibodies. Conversely, the antibodies block binding of IgG-sensitized erythrocytes to the NK cells and PMN and inhibit their ability to mediate cytotoxicity against antibody-sensitized tumor target cells. By using two-color immunofluorescence techniques, we characterize directly the lymphocyte population recognized by these antibodies and show that it is a homogeneous subset that does not bear markers of either B or T cells, with the exception of the 33,000 dalton antigen characteristic of suppressor/cytotoxic T cells present in 20 to 50% of the cells, and the 45,000 dalton receptor for sheep erythrocytes present on 80 to 90% of the cells. The phenotype of the cells reacting with the monoclonal antibodies corresponds to that of NK cells. Cross-competition experiments indicate that these antibodies detect at least two distinct epitopes on FcR, one ( B73 .1) preferentially expressed on NK cells and one or more ( 3G8 /Leu- 11a /Leu- 11b / VEP13 ) preferentially expressed on PMN. The lack of reactivity of these antibodies with B cells suggests that human B cells bear a different FcR from that on NK cells and PMN.