A human B cell differentiation antigen selectively expressed on mature B cells identified by a monoclonal antibody (HB-2)

A monoclonal IgM antibody (HB-2), produced against a membrane antigen on the Raji, B cell line, reacted by indirect immunofluorescence with 2 to 40% of lymphoblasts from the B cell lines, Raji, Daudi, SN-1036, and SB but not with other types of cell lines, including pre-B, myeloid, melanoma, or T cells. HB-2 antibody reacted with 10 ± 3% of normal blood mononuclear cells, and was unreactive with monocytes, granulocytes, platelets, or erythrocytes. Two-color immunofluorescence revealed that HB-2 antigen expression was confined to cells bearing surface Ig. An interesting finding was the fact that 25% of plasmablasts induced by pokeweed mitogen also expressed the HB-2 antigen. However, pre-B and plasma cells from normal bone marrow did not express the HB-2 antigen either on their membrane surface or in their cytoplasm. Analysis of 85 leukemias revealed that the HB-2 antigen was expressed on acute and chronic B cell leukemias and Burkitt's lymphomas, but not on malignacies of pre-B, T, myelocytic, or plasma cells. The results suggest that expression of the HB-2 antigen is confined to mature B cells.     

G蛋白β3亚单位基因C825T多态性与PTCA支架内再狭窄

目的 探讨G蛋白β3亚单位基因C825T多态性与PTCA支架植入后再狭窄之间的相关性。方法 采用多聚酶联反应结合限制性内切酶片断长度多态性分析方法(PCR-RFLP)检测50例经PTCA支架植入术后半年内发生再狭窄的患者和85例经PTCA支架植入在半年内未发生再狭窄的患者之间G蛋白β3亚单位基因C825T多态性。结果 再狭窄组G蛋白β3亚单位基因型频率(CC 14％、CT 54％、TT 32％),等位基因频率(C 41％、T 59％)与未狭窄组G蛋白β3亚单位基因型频率(CC31.8％、CT 44.7％、TT 23.5％),等位基因频率(C 54.2％、T 45.8％)比较统计学上有差异。结论 G蛋白β3亚单位基因C825T多态性可能与PTCA支架内再狭窄有关。     

Placental site trophoblastic tumor of the mediastinum

Choriocarcinoma has been described as the most frequent subtype of mediastinal germ cell tumors showing trophoblastic differentiation. We report a unique case of a placental site trophoblastic tumor, which developed in the mediastinum of a 14-year-old boy 2 years after the resection of a mature teratoma. The recurrent tumor was composed of a grossly hemorrhagic and necrotic mass. Histologically, diffusely infiltrating large polygonal cells with focal nodular growth and a teratomatous part containing mature intestinal, respiratory, and squamous epithelium with adjacent cutaneous adnexal structures were found. The typical morphologic features included vessel wall infiltration by the neoplastic cells with fibrinoid deposits and geographic necroses within the tumor masses. Characteristic diffuse positivity for melanoma cell adhesion molecule and human leucocyte antigen G was found on immunohistochemical investigation, confirming the diagnosis of placental site trophoblastic tumor. The patient died 1 year later after polychemotherapy. The outcome of this rare tumor is similar to the reported poor clinical outcome in patients with mediastinal choriocarcinomas.     

Presence of hepatitis B surface antigen mutant G145R DNA in the peripheral blood leukocytes of the family members of an asymptomatic carrier and evidence of its horizontal transmission

An asymptomatic carrier and all six of his family members were detected positive for HBV DNA in their peripheral blood leukocytes (PBL), by polymerase chain reaction. Direct sequencing of the amplified DNA revealed that the HBV DNA from the carrier and his wife was of subtype ayw. Interestingly, the amplified HBV DNA from the five other members of the family was found to be not only of subtype adw but also contained G to A mutation at nucleotide position 587. This indicates the presence of established vaccine escape mutant of the virus (G145R) and suggests two different sources of infection within the family. Southern blot hybridization of EcoR1 digested DNA from PBL indicated presence of HBV DNA, integrated into cellular DNA and also in the form of free viral DNA. The study not only establishes the persistence of surface mutant G145R HBV DNA, within the PBL of HBsAg negative individuals from the non-vaccinated random population, but also suggests possible horizontal transmission of the mutant among the family members although none of the family members has received immunoprophylaxis against HBV or had clinically apparent disease or any other known risk factors of HBV infection. As all of them were seronegative for HBsAg/antiHBc, the presence of G145R mutant in the PBL signaled possibility of spread of the vaccine escape mutant virus by blood transfusion, unsafe injection practices or through sexual root.     

Characterization of idiotopes on MOPC 315 IgA using monoclonal antiidiotypic antibodies

The isologous antiidiotypic response in BALB/c mice to immunization with the DNP-binding IgA myeloma protein, MOPC 315, alters the expression of the anti-DNP antibody repertoire and confers immunity against MOPC 315 myeloma tumors. In order to characterize the idiotopes on MOPC 315 IgA which elicit this response we have isolated four monoclonal antiidiotypic antibodies (AIA), D10 (IgG_2a), A2(IgG₁), G3 (IgG_2b) and F1 (IgG_2a), produced by splenocytes of BALB/c mice immunized with MOPC 315 IgA in three independent fusion experiments. These AIA react with MOPC 315 IgA. reassociated H³¹⁵ L³¹⁵ and F³¹⁵_V but not with free H³¹⁵, L³¹⁵, V³¹⁵_H or V³¹⁵₂. In addition the AIA do not react with the closely related DNP-binding IgA myeloma protein, MOPC 460, suggesting that they are directed against private idiotopes on MOPC 315 IgA. These idiotopes can be divided into two groups. Group I, defined by D10, A2 and G3 consists of two overlapping idiotopes, one of which is related to the hapten-binding site. The two idiotopes are formed by an interaction of amino acids in H³¹⁵ and L³¹⁵. Group II defined by F1 consists of one idiotope which is related to the hapten-binding site. This idiotope is comprised of an aminoacid sequence on H³¹⁵ which requires an interaction with either L³¹⁵ or L⁴⁶⁰ for expression. A2 and G3 react identically with the same idiotope but were derived from two independent fusion experiments. This indicates an identity of AIA clonotypes among individual mice and suggests that the isologous AIA response to MOPC 315 IgA is restricted.     

Reconstitution of humoral immunity during pregnancy

BACKGROUND: Recently, increasing attention has been paid to hormonal regulations of the immune system. MATERIALS AND METHODS: In this study, cord sera and the corresponding maternal sera were obtained at delivery. Sera from pregnant women were obtained at early, middle, and late stages of pregnancy. These sera were tested for titer and avidity of measles or mumps virus-specific immunoglobulin G (IgG) by means of a single-dilution, urea-denaturation enzyme-linked immunosorbent assay method. RESULTS: A positive and significant correlation was found between the titer and avidity of the virus-specific IgG, both in the cord sera and in the maternal sera. This correlation was established already at the early stage of pregnancy. There were no such correlations found in nonpregnant individuals. CONCLUSIONS: This is the first observation in human subjects that the avidity and concentration of the virus-specific IgG had a positive and significant correlation. Pregnancy must have some significant effects on the regulation of humoral immunity.     

Effects of the C-terminal Peptide of the αs subunit of the G protein on the regulation of Adenylyl Cyclase and Protein Kinase A activities by Biogenic Amines and Glucagon in Mollusk and Rat Muscles

The C-terminal parts of the subunits of heteromeric G proteins play an important role in the functional linkage of G proteins with receptors of the serpentine type. The present report describes studies of the effects of the C-terminal octapeptide 387–394 of the _s subunit of the mammalian G protein on the transmission of the hormonal signal via the hormone-sensitive adenylyl cyclase signal system, whose major components are receptors of the serpentine type, G proteins, and the enzymes adenylyl cyclase and protein kinase A. The peptide synthesized here, 387–394 amide (10^–7 - 10^–4 M), dose-dependently decreased adenylyl cyclase and protein kinase A activities stimulated by serotonin and glucagon in smooth muscle from the freshwater bivalve mollusk Anodonta cygnea and by the agonist isoproterenol in rat skeletal muscle. At a concentration as low as 10^–7 M, the peptide released potentiation of the stimulatory effects of hormones on adenylyl cyclase activity due to the non-hydrolyzable guanine nucleotide analog Gpp[NH]p. At the same time, it had almost no effect on the stimulation of adenylyl cyclase activity by non-hormonal agents (NaF, Gpp[NH]p, and forskolin). The inhibitory effects of hormones on adenylyl cyclase and protein kinase A activities persisted in the presence of the peptide. Our data demonstrate the importance of the C-terminal part of the _s subunit of the stimulatory G protein for its functional linkage with receptors of the serpentine type and throw light on the molecular mechanisms of the interactions between G proteins and receptors.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 7, pp. 837–850, July, 2003.     

Anti-neutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis: anti-cathepsin G and a novel antibody correlate with a refractory type

We analysed the clinical significance of ANCA in patients with ulcerative colitis. On either an indirect immunofluorescence assay or an ELISA with fixed neutrophils, 71% (25/35) of the patients were positive for ANCA. However, only half of them reacted with either cathepsin G or lactoferrin. Western blot assays revealed positive bands in 40% (10/25) of the antibody-positive patients. The sizes of the bands detected were ≈58, 47, 44, 40, and 28 kD. No significant correlation was found between the ANCA positivity and various variables, i.e. disease activity, extent of lesion, or treatment of the disease. The anti-cathepsin G and 28-kD positivity, however, significantly correlated with a refractory type of ulcerative colitis.     

Time-dependent study of the antibody response to sperm-whale myoglobin: recognition of the antigenic sites is unaltered over an extended period of immunization

We have recently shown that the antigenic structure of sperm-whale myoglobin is not dependent on the host species in which the antisera are raised. The purpose of the present work was to determine whether or not the molecular immune recognition of a protein by antibody is subject to a time-dependency. We have investigated the recognition of the antigenic sites by serial antisera obtained in two rabbits at different times after the initial immunization, from the earliest bleeding with detectable antibodies (9 days) up to a year. The specificity of these antisera was determined by their cross-reactions with 13 myoglobins from different species. The reactivity was measured by quantitative immunoadsorbent titration studies from the amount of radioiodinated antibodies that could be bound maximally (i.e. plateau binding values) by immunoadsorbents of each myoglobin. From these studies and our recent structural analysis, which enabled us to identify for each of these myoglobins the regions retaining reactivity with antibodies to sperm-whale myoglobin, we have concluded that following maturation of the immune response the antigenic recognition of a protein (i.e. the regions that are recognized as antigenic) is not dependent upon the time antisera are obtained after the first immunization. In the early periods of the response, fluctuations are observed in the relative immunodominance of the sites. This further confirms our earlier conclusions that the antigenic sites on a protein are structurally inherent in the protein.     

SELECTIVE HABITUATION OF GALVANIC SKIN RESPONSE COMPONENT OF THE ORIENTATION REACTION TO AN AUDITORY STIMULUS

The prediction from Sokolov's (1960) theory that, following OR habituation, size of OR return is proportional to the amount of difference between the new stimulus and the habituating stimulus was tested using an auditory stimulus varying in frequency and intensity. Five Ss were allocated to each of 16 conditions, three conditions involving changes in frequency, three involving changes in intensity, nine involving changes in both frequency and intensity, with one control condition involving a repetition of the habituating stimulus. Following habituation of the GSR component of the OR to a criterion of response failure for three successive trials, magnitude of GSR under the 16 conditions was measured. Contrary to Sokolov's theory, only increase in intensity had a significantly different effect on OR return. More importantly, it was found that Ss habituating rapidly to the initial stimulus were less likely to show OR return to stimulus change. It was concluded that individual differences in habituation rate may be more important than stimulus difference effects in selective habituation.