Idiotypic-anti-idiotypic B cell interactions generated against a protective antigen of a morbillivirus in mice

The idiotypic network theory (N. K. Jerne, Ann. Immunol. 125, 373-389, 1974) predicts that any antibody that can be made by an individual would have its preexisting specific complementary B cells in its germline repertoire. We transplanted syngeneic BALB/c mice with live hybridoma cells and demonstrated the simultaneous presence of interacting idiotypic and anti-idiotypic B cells in an individual animal by immuno-cytoadherence assays. Furthermore, we demonstrate that interacting B cells displaying idiotypic and anti-idiotypic antibodies are subjected to lysis by complement. It is therefore tempting to speculate that this complement-sensitive interaction between idiotypic and complementary anti-idiotypic B cells in vivo may provide a mechanism for the regulation of B cell populations.

Risk factors for laparoscopically confirmed pelvic inflammatory disease: findings from Mumbai (Bombay), India

OBJECTIVES

Sexually transmitted diseases (STDs) are an important cause of pelvic inflammatory disease (PID) but have often not been detected in microbiological studies of Indian women admitted to hospital gynaecology wards or private clinics. In this cross sectional study, women living in the inner city of Mumbai (Bombay) were investigated for socioeconomic, clinical, and microbiological risk factors for PID.

METHODS

Microbiological tests and laparoscopic examination were carried out on 2736 women aged < or = 35 years who came to a health facility with suspected acute salpingitis or infertility or for laparoscopic sterilisation. 86 women with a clinical diagnosis of PID were not referred for laparoscopy although their characteristics are described. Associations between various risk factors and PID status were investigated and logistic regression performed on all factors that remained significant.

RESULTS

Of women with a laparoscopically confirmed evaluation, 26 women had acute and 48 chronic pelvic infection. Independent risk factors for PID were later age at menarche (> or = 14 years), a history of stillbirth and no previous pregnancy, history of tuberculosis, STD, dilatation and curettage or previous laparoscopy, and presence of Gardnerella vaginalis.

CONCLUSIONS

It is concluded that STD related risk factors applied to only a small proportion of PID cases and that other determinants of PID are important, including obstetric complications, invasive surgical procedures such as laparoscopy, and tuberculosis.

Reproductive tract infections, gynaecological morbidity and HIV seroprevalence among women in Mumbai, India

Reported are the prevalence of reproductive tract infections and their contribution to pelvic inflammatory disease (PID), as well as the seroprevalence of human immunodeficiency virus (HIV), among women living in three inner city wards of Mumbai, India. Women aged < or = 35 years were recruited and screened as cases if they had been admitted to hospital for gynaecological investigation for suspected PID (n = 151) or infertility (n = 295); controls were healthy fertile women attending for laparoscopic tubal ligation (n = 2433). The women were mainly of low socioeconomic status. A total of 59.4% were migrants and 14.9% of these came to Mumbai to seek treatment. Cases reported a history of adverse pregnancy outcomes significantly more often than controls, and 30.5% of suspected PID cases had previously undergone laparoscopic tubal ligation. At examination 24.2% of cases and 8.4% of controls had a vaginal discharge. Pelvic infection was confirmed in 42.0% of suspected PID cases and 14.6% of infertile cases for whom diagnostic laparoscopy was performed. The prevalence of sexually transmitted diseases was low: Chlamydia trachomatis was found in 0.2%; and Neisseria gonorrhoeae was cultured from the cervix in only four cases. Neither of these infections was detected in laparoscopic aspirates. The prevalence of HIV1/2 infections in unlinked samples was 1.9%. Sexually transmitted diseases were not major factors leading to gynaecological morbidity. Heterosexual spread of HIV infection to this population of married women is still relatively low but needs to be carefully monitored. The gynaecological morbidity detected may be a consequence of widespread use of invasive methods of fertility regulation.

Primary structure of sesbania mosaic virus coat protein: its implications to the assembly and architecture of the virus

Sesbania mosaic virus (SMV) is a plant virus that infects Sesbania grandiflora plants in Andhra Pradesh, India. The amino acid sequence of the coat protein of SMV was determined using purified peptides generated by cleavage with trypsin, chymotrypsin, V8 protease and clostripain. The 230 residues so far determined were compared to the corresponding residues of southern bean mosaic virus (SBMV), the type member of sobemoviruses. The overall identity between the sequences is 61.7%. The amino terminal 64 residues, which constitute an independent domain (R-domain) known to interact with RNA, are conserved to a lower extent (52.5%). Comparison of the positively charged residues in this domain suggests that the RNA-protein interactions are considerably weaker in SMV. The residues that constitute the major domain of the coat protein, the surface domain (S-domain, residues 65-260), are better conserved (66.5%). The positively charged residues of this domain that face the nucleic acid are well conserved. The longest conserved stretch of residues (131- 142) corresponds to the loop involved in intersubunit interactions between subunits related by the quasi 3-fold symmetry. A unique cation binding site located on the quasi 3-fold axis contributes to the stability of SMV. These differences are reflected in the increased stability of the SMV coat protein and its ability to be reconstituted with RNA at pH 7.5. A major epitope was identified using monoclonal antibodies to SMV in the segment 201-223 which contains an exposed helix in the capsid structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Behaviour of the germ cell specific lamin through mammalian spermatogenesis as probed with monoclonal antibodies

We had earlier identified a 60 kDa nuclear lamin protein (lamin(g)) unique to the germ cells of rat testis which was subsequently shown to be antigenically conserved in germ cells of grasshopper, rooster, frog and plants. We have now obtained eight monoclonal antibodies in mouse against this lamin(g) antigen. While all the eight Mabs reacted with lamin(g) antigen in an immunoblot analysis, only three Mabs (A11C7, A11D4, C1F7) showed strong reactivity in the immunofluorescence analysis of the germ cells. The Mabs A11C7 and A11D4 showed a slight cross-reactivity with rat liver lamin B. Indirect immunofluorescence analysis of pre-meiotic, meiotic and post-meiotic germ cells with Mabs have shown that while the lamin(g) is localized in the lamina structures of spermatogonia and round spermatids, it is localized to the phase dense regions of pachytene spermatocytes which is in conformity with our previous observations using rabbit polyclonal antibodies. The localization of the antigen in the germ cells was also confirmed by immunohistochemical staining of the thin sections of seminiferous tubules. By immunostaining the surface spread pachytene spermatocytes, the antigen was further localized to the telomeric ends of the paired homologous chromosomes. Using anti-somatic lamin B antibodies, we have also demonstrated the absence of somatic lamins in meiotic and post-meiotic germ cells. The lamina structure of pre-meiotic spermatogonial nucleus contains both somatic lamin B and lamin(g) as evidenced by immunofluorescence studies with two differently fluorochrome labelled anti-lamin B and anti-lamin(g) antibodies. The selective retention of lamin(g) in the pachytene spermatocytes is probably essential for anchoring the telomeric ends of the paired chromosomes to the inner nuclear membrane.

Deficiency of malic enzyme: a possible marker for malignancy in lymphoid cells

Soluble malic enzyme (MEs) has been examined in long-term human lymphoid cell lines cultured from 101 individuals. In 65 out of 66 lines derived from people without lymphoreticular malignancy the enzyme was very active. Lines established from 35 individuals with various forms of lymphoreticular malignancy were also examined, including in some cases more than 1 line derived from the same patient. In all cases where the cell line was thought to be derived from normal cells MEs was active, but in 27 out of 29 lines thought to be derived from malignant cells (from 25 patients) MEs was not detected. In the case of two patients with chronic lymphatic leukaemia 'normal' lines active for malic enzyme, and 'leukaemic' lines lacking malic enzyme, had been cultured from the same individual. Preliminary investigations of the lack of malic enzyme in somatic cell hybrids derived from lymphoma and leukaemia cell lines are compatible with an alteration at the level of the structural locus MEs on chromosome 6. However, the restoration of MEs activity in one line by fusion with mouse teratocarcinoma cells suggests that the alteration may be of a regulatory nature.

Establishment of a lymphoid cell line from leukemic cells of a patient with chronic lymphocytic leukemia

Two lymphoid cell lines were established from a patient with chronic lymphocytic leukemia by infecting blood cells with Epstein-Barr virus (EBV). Studies of morphology, glucose-6-phosphate dehydrogenase, malic enzyme, immunoglobulin, and chromosomes of the two lines indicated that one of them originated from leukemic cells while the other arose from residual normal blood cells. The morphology and capacity for immunoglobulin secretion in the line that arose from leukemic cells were similar to those found in EVB-carrying lymphoblastoid cell lines grown from patients without neoplasia and differed from those seen in fresh chronic lymphocytic leukemia cells. These observations suggest that the introduction of EBV into the leukemic cells may have caused them to differentiate in a fashion similar to that noted in normal B cells after exposure to EBV.

Chromosome analyses of lymphoid cell lines derived from patients with chronic lymphocytic leukemia

To study chromosome complements of chronic lymphocytic leukemia cells, six Epstein-Barr virus-transformed lymphoid lines were established from two patients with this disease who were heterozygous for the X-chromosome-linked enzyme glucose-6-phosphate dehydrogenase (G6PD). Immunoglobulin and G6PD were used as markers of the leukemic versus normal cell origin of the cell lines. The two lines, derived from putative normal cells, had no chromosomal changes. In contrast, chomosome abnormalities were found in each of the four cell lines of presumed leukemic cell origin. Although the chromosome aberrations are not as specific as the Philadelphia chromosome, there appears to be non-random involvement in chronic lymphocytic leukemia of some chromosomes, such as the No. 12.

Moloney lymphoma cells express a polyprotein containing the GAG gene-coded p15 and the Moloney leukemia virus-induced cell surface antigen (MCSA)

The relationship between MCSA and the viral structural proteins in YAC Moloney lymphoma cells was further investigated by using membrane immunofluorescence and immunoadsorbent columns. As previously observed, MCSA showed only minimal capping and thereby differed in behaviour from gp70, p30 and p12 virion antigens. Whereas antibody-induced capping of gp70 did not change the membrane distribution of MCSA, co-capping was observed between MCSA and p30 and p12 gag protein antigens. This indicated that, whereas MCSA is distinct from gp70, it is linked to p30 and p12 on the membrane of living cells. It was then attempted to isolate MCSA on anti-p30 and anti-p15 immunoadsorbent columns from solubilized YAC cells. Contrary to what was expected, no MCSA was found to the anti-p30 column. On the other hand, a part (10-15%) of the MCSA was bound to the anti-p15 column, indicating that MCSA is linked to the gag p15.