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Biomedical subjects

P D Griffiths

Publications and source records attributed to P D Griffiths.

At least 271 records · Page 15Linked to original sources

Immunity to rubella among women of child-bearing age.

The results of testing for rubella antibodies in over 6000 sera from women of child-bearing age are reported and analysed according to pregnant state, age, country of origin and social class. There was no difference between the rubella seroprevalence rates in women who were pregnant and in those who were contemplating pregnancy in the future. Likewise, women (either pregnant or non-pregnant) who were young enough to have been offered rubella vaccine at school were not more likely to be immune to rubella than were older women. Rubella seropositivity rates were not influenced by social class but significantly higher rates were found in women born in European or Arabian than in African or Asian countries. We conclude that the national scheme for rubella immunization has not reduced the number of women susceptible to rubella entering pregnancy in this Health District and that greater attention should be paid to immunization of women of child-bearing age from African or Asian countries.

Adolescent↗

Infection with human immunodeficiency virus (HIV) and cytomegalovirus in a London health district 1980-4.

By testing serum samples taken between 1980 and 1984 from men attending a department of sexually transmitted diseases, it was shown that antibodies to human immunodeficiency virus (HIV) first appeared in 1981. Homosexual men were significantly more likely to have antibodies to HIV and to cytomegalovirus (CMV) than were heterosexual men attending the same clinic. This shows that homosexuals are exposed to both HIV, the cause of the acquired immune deficiency syndrome (AIDS), and to CMV, which can reactivate to cause life threatening disease once immunosuppression has developed. All homosexuals, not just those with antibodies against HIV, had raised levels of CMV antibodies. This suggests that they experience frequent antigenic stimulation after reinfections with CMV or reactivation of endogenous virus.

Adolescent↗

Transfer of a functioning humoral immune system in transplantation of T-lymphocyte-depleted bone marrow.

To test the effect of transplantation of T-cell-depleted bone marrow on recipient immune function the results of pre-transplantation immunisation with tetanus toxoid and hepatitis-B vaccine were studied in 38 donor-recipient pairs. Immunisation of the donor alone resulted in transfer of an antibody response to the recipient; immunisation of both donor and recipient resulted in potentiation of the antibody response in both magnitude and duration. These findings indicate that donor T-cell-depleted marrow can transfer humoral immunity to the recipient and that appropriate pre-transplant immunisation schedules may be of benefit to the recipient.

Adolescent↗

Detection of cytomegalovirus by ELISA in urine samples is inhibited by beta 2 microglobulin.

During development of an enzyme immunoassay for the detection of cytomegalovirus (CMV) we previously discovered that virus found naturally in urine specimens could not be captured onto the solid phase by CMV-specific monoclonal antibodies, whereas these same antibodies could capture CMV from cell culture supernatants. We now report that urine from normal CMV-seronegative individuals contains a substance of molecular weight 11-12,000 daltons that inhibits the ELISA detection of cell culture-grown CMV. The addition of a known urinary protein of this molecular weight, beta 2 microglobulin (beta 2m; 11,700 daltons), inhibited the detection of cell culture-grown CMV in the ELISA over the concentration range found in clinical urine samples. In contrast, another low molecular weight urinary protein, lysozyme, had no inhibitory effect. beta 2m caused inhibition only when added to the virus preparation and not to the antibody-capture stage. We conclude that beta 2m in urine prevents the detection of CMV by ELISA by binding to the virus and masking its antigenic determinants and we calculate that of the order of 10(5) molecules of beta 2m bind to each particle of cell culture-grown CMV. We postulate that CMV in fresh urine specimens is similarly coated with beta 2m, accounting for the failure to detect it by ELISA.

Antigens, Viral↗

An improved radioimmunoassay method for the detection of IgG antibodies against cytomegalovirus.

The non-specific binding seen with human sera in a radioimmunoassay for the detection of IgG antibodies specific for CMV can be reduced greatly by using a murine monoclonal antibody as a radiolabelled detecting antibody. Such non-specific binding formerly obtained with a polyclonal detecting antibody was due to the binding of the polyclonal reagent to factors on the solid phase other than IgG molecules.

Antibodies, Monoclonal↗

Production of anti-cytomegalovirus antibody following T-cell depleted bone marrow transplant.

The serological status to cytomegalovirus (CMV) was examined in 24 patients with no detectable CMV excretion, following T-lymphocyte depleted bone marrow transplantation. The results show that seropositive recipients continue to produce CMV antibody regardless of the serological status of the donor but that seronegative recipients fail to produce CMV antibody even when the donor is seropositive. These findings suggest that when an effective CMV vaccine becomes available vaccination of the donor would be unlikely to confer protection on the recipient but that vaccination of the recipient may achieve this.

Antibodies, Viral↗

Virological and serological diagnosis of cytomegalovirus infection in bone marrow allograft recipients.

To detect cytomegalovirus (CMV) infections, a total of 1,074 cultures of urine, saliva, or blood were collected weekly from 43 consecutive patients undergoing allogeneic bone marrow transplantation. Twenty-three patients were seronegative before transplant and primary infection occurred in 2 (9%). Twenty patients were initially seropositive and recurrent infections occurred in 5 (25%). Three patients in the recurrent group had proven CMV pneumonitis; viraemia was detected in two recipients, while the third had CMV isolated only from bronchial lavage fluid. The serological response of the 43 patients was defined by testing 559 serial sera for specific IgG and IgM antibodies by radioimmunoassay. Passive acquisition of IgG antibodies from blood products was found in 78% of initially seronegative recipients. One patient with primary infection responded in a pattern typical of immunocompetent individuals with long-term production of specific IgG and transient production of specific IgM antibodies. The second patient also had a typical response, but this was delayed until several weeks after the start of virus excretion. In patients with recurrent infections, specific IgM production did not correlate with episodes of virus excretion. Three of five such patients failed to mount a specific IgM response, and these were the only patients in the study to develop CMV pneumonitis. We conclude that CMV infection in bone marrow recipients can only be diagnosed by detection of virus; therefore, the ability of these patients to mount humoral immune responses should not be relied upon for diagnostic purposes.

Antibodies, Viral↗

Detection of cytomegalovirus in urine samples by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of cytomegalovirus (CMV) in urine using monoclonal antibodies directed against CMV as a capture for viral antigen. The assay was capable of detecting virus at 10(2.3)TCID50/ml as determined by titration of stock virus, strain Ad169. The assay was found to have a sensitivity of 65% and a specificity of 100% when 73 coded stored urine specimens were examined. Assuming that the poor sensitivity was due to loss of antigen following storage, we proceeded to analyse fresh urine specimens. Surprisingly, the assay gave negative results with 46 fresh urines known to contain CMV; however, following storage at +4 degrees C for two weeks, 35 (76%) of these samples gave ELISA results in the positive range. This detection of CMV, after storage at +4 degrees C, could be due to degradation of virus particles leading to release of soluble glycoproteins into the medium or to the presence of an inhibitory substance in fresh urine that is destroyed during storage.

Antibodies, Monoclonal↗

Detection of cytomegalovirus by DNA-DNA hybridization employing probes labelled with 32-phosphorus or biotin.

Various factors influencing the detection of human cytomegalovirus (HCMV) in infected cells by DNA-DNA hybridization have been investigated. Employing the Hind III O fragment of HCMV AD169 labelled with 32P, we found that detection sensitivity was highly influenced by the method employed for extraction of DNA from infected cells. Excision of the Hind III O fragment from the vector by restriction endonuclease digestion prior to 32P-labelling further improved the detection capability of the probe. Similarly, cytomegalovirus (CMV) DNA detection employing biotin-labelled probes and streptavidin/alkaline phosphatase in the hybridot assay was also highly dependent on the method of DNA extraction prior to hybridization. Finally, we describe an in situ assay employing a biotin-labelled probe and fluorescein-conjugated avidin to detect CMV DNA in cultured cells.

Biotin↗