Search PubMed⌕ Search

Biomedical subjects

J M Best

Publications and source records attributed to J M Best.

At least 55 records · Page 3Linked to original sources
PubMed1994

Rubella reinfection; role of neutralising antibodies and cell-mediated immunity.

BACKGROUND: Rubella virus may be transmitted to the fetus following rubella reinfection in early pregnancy. The mechanisms responsible for maternal-fetal transmission in women with pre-existing rubella antibodies are, however, unclear. OBJECTIVES: To evaluate the protective role of rubella specific neutralising antibodies and cell-mediated immunity in rubella reinfection. STUDY DESIGN: Rubella Nt antibodies were measured in sera obtained from: women who experienced rubella reinfection during pregnancy, volunteers experimentally challenged with rubella vaccine and women attending for routine rubella antibody screening. Cell-mediated immunity was assessed by measuring rubella specific LT responses among women who had experienced rubella reinfection during pregnancy. RESULTS: Some women experienced rubella reinfection during pregnancy despite the presence of Nt antibodies in sera obtained before contact. Only 2 of 13 (15.3%) volunteers with low levels (< 15 IU/ml) of rubella antibody had detectable Nt antibodies prior to experimental challenge. Despite this, they did not develop rubella viraemia following challenge and virus excretion was detected in only one case, although the majority (11/13, 84.6%) demonstrated a significant rise in antibody titre. Among pregnant women screened as having a low level of rubella antibody antenally, only 37% had detectable Nt antibodies. Among 23 women who experienced rubella reinfection during pregnancy 4 months to 6 years (mean 32 months) previously, 20 (86.9%) had a positive rubella-specific LT response. Only one of 4 cases where rubella virus was transmitted to the fetus failed to produce a a specific LT response. CONCLUSIONS: This study indicates that rubella reinfection is not associated with a lack of Nt antibodies or persistent impairment of rubella-specific LT responses.

Journal Article↗
PubMed1994

Recombinant rubella E1 fusion proteins for antibody screening and diagnosis.

BACKGROUND: Until rubella is eradicated there will be a continuing need for rubella antibody surveillance. Antigen production using recombinant DNA technology may be a viable alternative to traditional techniques of producing antigens for enzyme immunoassays (EIAs). OBJECTIVES: To investigate the potential of bacterial fusion proteins containing rubella E1 protein sequences for use in EIAs to detect rubella antibodies. STUDY DESIGN: Purified bacterial fusion proteins containing rubella E1 sequences to be used as antigens in EIAs and compared to 'traditional' assays using virus derived antigens for rubella antibody screening. RESULTS: cDNA clones coding for the complete rubella E1 protein sequence and subfragments of E1 were modified for expression as carboxy terminal fusions with either beta-galactosidase or glutathione-S-transferase. beta-galactosidase fusions with the complete E1 coding sequence or amino acids 201 to 307, which contain known epitopes, resulted in the production of predominantly insoluble fusion proteins unsuitable for use in EIA. Nine glutathione-S-transferase-E1 fusion proteins were produced with individual fusion proteins exhibiting varying properties with regard to the levels of protein produced, apparent stability, solubility and the potential for affinity purification using glutathione agarose. Reduction of the E1 component to only 44 amino acids containing three B-cell epitopes (Terry et al., 1988) produced an abundant soluble GST-E1 fusion protein (3.5 mug/ml), which could be affinity purified using glutathione agarose. This fusion protein has been successfully used in EIA to detect rubella antibodies. CONCLUSIONS: We have shown that GST-E1 fusions have potential as antigens in tests for rubella antibodies.

Journal Article↗
PubMed1994

Detection of E5 oncoprotein in human papillomavirus type 16-positive cervical scrapes using antibodies raised to synthetic peptides.

Polyclonal antibodies were raised to partial and full-length synthetic peptides of human papillomavirus type 16 (HPV-16) E5. Antisera specificity for HPV-16 E5 was demonstrated by their ability to recognize not only their peptide immunogens but also full-length peptide and a glutathione S-transferase-E5 fusion protein. The most reactive antiserum, PE-6, raised to a full-length peptide, was used in Western blot analysis to identify HPV-16 E5 protein from exfoliated cervical cells. A strong, single band at approximately 20K was detected in two of six HPV-16-positive samples from women with a history of low-grade cervical intraepithelial neoplasia. The apparent M(r) by SDS-PAGE suggests that HPV-16 E5 forms homodimers in vivo, but not through cysteine linkage.

Antibodies, Viral↗
PubMed1994

Cancer associated human papillomaviruses: perinatal transmission and persistence.

OBJECTIVE: To demonstrate the perinatal transmission and persistence of the cancer associated human papillomavirus types 16, 18, 31 and 33. DESIGN: Cervical swabs were taken from pregnant women between 20 and 38 weeks of gestation. Buccal and genital swabs were taken from infants at 24 h and at six weeks after delivery and examined for HPV-16, -18, -31 and -33 DNA by the polymerase chain reaction. SETTING: Maternity Unit at St Thomas's Hospital, London. SUBJECTS: Thirty-one pregnant women, 16 with a previous history of cervical intraepithelial neoplasia or genital warts, or both, and their 32 infants (one set of twins). RESULTS: Twenty of the 31 (65%) women were positive for HPV-DNA prior to delivery. Twelve of 32 (38%) and eight of 31 (26%) infants were HPV-DNA positive at 24 h and six weeks respectively. Swabs taken at 24 h demonstrated HPV type 16 in five mother-infant pairs and HPV type 18 in two mother-infant pairs. Dual infections with HPV types 16 and 18 were demonstrated in swabs from three mother-infant pairs. At six weeks, HPV-16 was demonstrated in swabs from six infants and HPV-18 in swabs from two infants. CONCLUSIONS: Perinatal transmission of human papillomavirus types 16 and 18 occurred in 55% cases. Persistent human papillomavirus infection was demonstrated at six weeks of age. Whether acquisition of human papillomavirus during the perinatal period predisposes to an increased risk of cervical intraepithelial neoplasia among female infants in later life remains to be established. Information on the persistence of perinatally acquired human papillomavirus is required before rational vaccination programmes can be considered.

Adolescent↗
PubMed1994

Reasons for rubella susceptibility among pregnant women in west Lambeth.

One hundred and thirty-three pregnant women who delivered at St Thomas' Hospital, in 1990 were noted to require rubella vaccination post partum. Fifty-three (39%) had completed a telephone questionnaire in order to determine reasons for susceptibility to rubella. Laboratory reports confirmed that 92 women were rubella seronegative and 27 had low levels of antibody. Of the 53 women interviewed, 25 gave a history of one or more rubella immunizations, 20 had no history of immunization and vaccination history was unknown for eight. Eleven of the 20 unvaccinated women had not been at school in the UK between 11 and 14 years of age. Eighty-seven per cent of the patients' general practitioners had no knowledge of their patients' rubella antibody status. Ninety-four per cent of the 133 women received rubella vaccine post partum. The Department of Health guidelines should be more vigorously implemented in order to identify and immunize remaining rubella susceptible women of child-bearing age. Susceptibility among women with a history of rubella immunization suggests that the seroconversion rate following rubella immunization in clinical practice may be lower than in vaccine trials.

Africa↗
PubMed1993

Slow maturation of IgG1 avidity and persistence of specific IgM in congenital rubella: implications for diagnosis and immunopathology.

Without appropriately timed specimens, serological confirmation of congenital rubella infection may be a problem. We have compared the persistence of specific IgM and low avidity specific IgG1 in 141 sera from 120 cases of serologically confirmed congenital rubella infection with the known time scales for postnatal primary rubella. The results demonstrate that the maturation of the immune response to the rubella virus is abnormally slow in congenital rubella cases both in terms of the isotype switch and especially the development of high avidity specific IgG1. Thus avidity studies may permit serological confirmation of congenital rubella for longer than is possible with tests currently in use. The pathological implications of prolonged low avidity antibody production are discussed.

Aging↗
PubMed1993

Towards vaccines against human papillomavirus type-16 genital infections.

Human papillomavirus type-16 (HPV-16) is strongly associated with cervical carcinoma and cervical intraepithelial neoplasia. It may soon be possible to develop prophylactic vaccines designed to induce neutralizing antibodies to HPV-16 virions in genital secretions and therapeutic vaccines to induce cytotoxic T-cell responses against HPV-16 early proteins in cervical intraepithelial neoplasia and cervical cancers. Although significant advances have been achieved, problems remain before such vaccines can be used routinely.

Animals↗
PubMed1993

Mapping of linear B cell epitopes on capsid proteins of bovine papillomavirus: identification of three external type-restricted epitopes.

Immunodominant, conserved and type-restricted external epitopes of bovine papillomavirus (BPV) major (L1) capsid protein have been identified using BPV particles and synthetic peptides. Antisera to disrupted BPV-1 recognized BPV-1 and BPV-2 particles in immune electron microscopy (IEM) studies and inhibited BPV-2-induced focus formation of NIH/3T3 cells. Thus BPV-1/BPV-2 cross-reactive epitopes occur on the surface of virions. The L1 protein appeared to be immunodominant as the antisera reacted with three dominant BPV-1/BPV-2 conserved B cell epitopes (amino acids 111 to 125, 131 to 145 and 191 to 205) in Pepscan assays of BPV-1 L1, whereas no common epitopes and less frequent antibody binding to peptides were detected in Pepscans of the L2 protein of BPV-1. Four discrete variable regions were identified in the sequences of L1 proteins of BPV-1 and BPV-2. Antisera against synthetic peptides corresponding to three of the four variable regions (amino acids 42 to 56, 435 to 449 and 485 to 499) of BPV-2 L1 caused clumping of BPV-2, but not of BPV-1, particles as examined by IEM, and antisera to one peptide (amino acids 485 to 499) inhibited BPV-2-induced focus formation of NIH/3T3 cells. These data suggest that these regions are type-specific BPV-2 L1 epitopes and that they occur on the virion surface. Although conformation-dependent epitopes remain to be identified on papillomaviruses, the linear epitopes identified in this study may be worthy of further study as constituents of experimental prophylactic vaccines.

3T3 Cells↗
PubMed1992

Detection of antibodies to a linear epitope on the major coat protein (L1) of human papillomavirus type-16 (HPV-16) in sera from patients with cervical intraepithelial neoplasia and children.

Antibodies to the major (L1) coat protein of human papillomavirus type 16 (HPV-16) in sera from patients with cervical intra-epithelial neoplasia (CIN) have been investigated by means of recombinant proteins and synthetic peptides. When L1-HPV-16 fusion proteins were used in immunoblot assays, no antibody reactivity was found in sera from 52 patients with CIN or from 21 unrelated children. Amino-acid sequence analyses indicated that L1-HPV-16 amino acids 473 to 492 may contain an HPV-16 type-restricted epitope since the greatest diversity occurs in this region. In the ELISA, seropositivity to peptides 473 to 492 was more common among CIN patients whose biopsies contained HPV-16 DNA (91%, 21 of 23) than among their children (24%, 5 of 21; p less than 0.001) or other CIN patients with HPV-16 DNA-negative biopsies (66%, 19 of 29; p less than 0.05), but was unrelated to the severity of the CIN lesion. Antibodies to L1-HPV-16 peptide 473 to 492 among seropositive CIN patients cross-reacted with the analogous L1-HPV-33, but not with the L1-HPV-6b peptide, and were predominantly IgM. In contrast, antibodies which recognized a less variable region of L1-HPV-16 (amino acids 279 to 293) showed no association with HPV-16 DNA status. Seropositivity to the L1-HPV-6b (amino acids 473-492) was less frequent (33%) among CIN patients and unassociated with HPV-16 DNA status (p greater than 0.1); however 51% (37 of 72) of patients with genital warts had antibodies to this peptide.

Amino Acid Sequence↗
PubMed1992

Persistence of specific IgM and low avidity specific IgG1 following primary rubella.

Persistence of specific IgM in sera following primary rubella infection was compared with the maturation of the specific IgG1 response. 206 sera, from 171 patients with primary rubella, taken 1 day to 2.5 years after onset of illness, were tested. Rubella-specific IgM was detected by M-antibody capture radioimmunoassay in 100% of sera taken 15-28 days after onset, but in only 9% taken 3-4 months after onset. However, using the diethylamine (DEA) shift value (DSV) method, low avidity specific IgG1 was detected in 91% sera taken at 3-4 months and at 5-7 months 21% of sera remained positive. Using an avidity index method, with urea in the wash buffer, none of the sera were positive for low avidity specific IgG1 beyond 3 months after onset. With DEA in the wash buffer, the number of sera positive rose to 38% at 3-4 months. Thus, the DSV method for detecting low avidity specific IgG1 is a useful additional test for confirming or refuting a diagnosis of primary rubella and is of particular value for assessing pregnant patients.

Antibodies, Viral↗
PubMed1992

Rubella virus strains show no major antigenic differences.

To determine whether antigenic differences occur among rubella virus strains, five wild-type strains of rubella virus isolated in the UK, the USA, and in Japan between 1964 and 1987 and four attenuated vaccine strains were compared employing a panel of 28 monoclonal antibodies in neutralization, haemagglutination-inhibition, enzyme immunoassay, and indirect immunofluorescence assays. No antigenic differences were detected which confirms that rubella vaccines will protect against circulating strains and that rubella antigens used in serological tests for screening and diagnosis will detect antibodies induced by all strains.

Antibodies, Monoclonal↗