Donald J. Jeffries

Synthesis and evaluation of some novel phosphoramidate derivatives of 3'-azido-3'-deoxythymidine (AZT) as anti-HIV compounds

A series of monophosphate triester derivatives of 3′-azido-3′-deoxythymidine (AZT), designed as membrane-soluble pro-drugs of the nucleotide (AZTMP), have been tested for activity against the human immunodeficiency virus (HIV-1). It has been found that when carboxyl-protected, amino-linked amino acids, and alkyl chains, are asymmetrically substituted on the 5′-phosphate a significant antiviral effect is observed. Moreover, the activity of the compounds is profoundly dependent on the structure of the phosphate moiety, and in particular on the nature of the amino acid.

Loss of cytomegalovirus infectivity after treatment with castanospermine or related plant alkaloids correlates with aberrant glycoprotein synthesis

Abstract Many plants contain polyhydroxyalkaloids which are potent inhibitors of glucosidases, enzymes involved in oligosaccharide trimming. These are important in determining the final configuration of specific glycoproteins. Human cytomegalovirus (CMV) encodes a number of glycoproteins, some of which ultimately reside in the outer envelope of the mature virion and are important for virus infectivity. Treatment with three polyhydroxyalkaloids, castanospermine (CAST), deoxynojirimycin (DNJ) and 2R,5R-dihydroxymethyl-3R, 4R-dihydroxypyrrolidine (DMDP) blocked the growth of infectious virus, as determined by yield reduction and plaque reduction assays. However, in the presence of CAST, CMV infected cells continued to shed virions into the extracellular medium, as determined by electron microscopy. Envelope glycoproteins of virions produced after treatment with CAST (2.5 mM) were immunoprecipitated with a monoclonal antibody (F5) specific for the gcI family of glycoproteins. Analysis by PAGE-SDS showed an absence of gcI complex 2 (gp52 disulphide-linked to gp130) with a proportional increase in gcI complex 1 (gp52 disulphide-linked to gp95). The results indicated that gp130 alone, or linked to gp52, was important for CMV infectivity. As well as being potential targets for antiviral agents against CMV, inhibitors of glycoprotein trimming reactions may define components of the virion surface important for infectivity.

Synthesis and anti-HIV evaluation of some phosphoramidate derivatives of AZT: Studies on the effect of chain elongation on biological activity

A series of phosphoramidate derivatives of the anti-HIV drug AZT has been prepared as membrane soluble pro-drugs of the bio-active nucleotide forms and evaluated in vitro against HIV-1. Terminal substituted alkyl amines have a pronounced anti-HIV effect: this effect declines upon increasing the length of the methylene spacer. The results are consistent with a mechanism of action involving intracellular cleavage of the phosphoramidate bond, and release of the nucleotide, or a derivative thereof. Full spectroscopic data are included on the products and their phosphorochloridate precursors.

AIDS and HTLV-III/LAV infection: consequences for obstetrics and perinatal medicine

Summary. This paper was prepared at the request of the Scientific Advisory Committee of the Royal College of Obstetricians and Gynaecologists It includes data distilled from many published and unpublished reports, including those presented at the International Conference on AIDS held in Atlanta, Georgia in April 1985. The urgency of the issues raised would seem to merit including all available data in this way.

Synthesis and anti-HIV Activity of Some Novel Phosphorodiamidate Derivatives of 3′-azido-3′-deoxythymidine (AZT)

The reaction of 3′-azido-3′-deoxythymidine (AZT) with phosphoryl chloride followed by amino acid methyl esters gave novel diamidate derivatives of AZT 5′-monophosphate (AZTMP). It was hoped that the 5′-phosphorodiamidates might act as membrane-soluble prodrugs of the bio-active free nucleotides of AZT. Five different amino acids were employed, covering a range of structures and polarities. The reaction was also conducted with propylamine, and with diethylamine. The derivatives were tested for their inhibitory effect on human immunodeficiency virus type 1 (HIV-1) proliferation in a human lymphoblastoid cell line. The amino acid derivatives were potent inhibitors of viral proliferation, small changes in structure leading to marked changes in activity.

Cytomegalovirus infections in pregnancy

Cytomegalovirus (CMV) is a cause of concern for several reasons. It is the commonest cause of intrauterine infection and some infected babies suffer from abnormalities which may be present at birth or develop during early postnatal life. Either a primary or recurrent infection may result in intrauterine infection. Early accounts of CMV in pregnancy were based on limited data coupled with attempts to extrapolate from our knowledge of congenital rubella. It is now evident that the two viruses present quite different problems and only by prospective studies can the risks be assessed. An editorial in the Lancet (1977) entitled ‘Cytomegalovirus in adults’ concluded with the following unsubstantiated recommendation. ‘At present the best chance of preventing the birth of at least some retarded infants is to identify those pregnant women without antibodies and to follow them serologically through early pregnancy. Those with seroconversion can then be offered termination.’ It is doubtful whether many people followed this advice and this is fortunate in the light of further knowledge. Two major studies of CMV infection in pregnancy have been in progress for several years in London and it is now possible to assess this recommendation on the basis of some factual information. In this issue (p. 307) Griffiths & Baboonian present the final report of a 7-year study, of primary CMV infection during pregnancy, conducted at St Bartholomew’s Hospital. The results of the first 3 years of the study have been reported previously (Griffiths et al. 1980). The incidence of primary CMV infection was found to be approximately twice that of rubella and, as one would expect, the pattern of infection was endemic with CMV and epidemic with rubella. Nine congenitally infected infants were identified from 46 pregnancies complicated by primary CMV infection. This is a low rate of intrauterine transmission compared with those found in other studies. Workers in Scotland, Sweden and London have previously reported transmission rates of 3 8 4 5 % . Only two women were symptomatic and one of them was immunocompromised. Primary infection early in pregnancy was associated with an excessive feta! loss (15.4% compared with 2.2% in controls). No problems followed infection early in pregnancy. One child infected late in the second trimester developed psychomotor retardation. With the development of a solid-phase radioimmunoassay system for detecting CMV-specific IgM it should soon be possible to screen for infection in early pregnancy. Griffiths & Baboonian have assessed the role of screening to identify infected pregnancies with a view to termination. They conclude that of 30 pregnancies in which the woman would have been offered termination, four resulted in fetal death, two produced babies with asymptomatic infection and one newborn infant died apparently for reasons other than CMV infection, the 23 uninfected babies are developing normally. Of the remaining 28 primary infections diagnosed after the age of legal viability all are normal except for the one child who developed psychomotor retardation. On this evidence termination for early primary infection cannot be recommended and, since CMV is frequently transmitted to the fetus by recurrent infection in the mother at any stage in pregnancy, there is at present no rational basis for antibody screening. Detailed follow-up of the children in this study has recently been published by Preece et al. (1983). Another important study is in progress and preliminary findings have been published by Peckham et al. (1983). This is a prospective study of all pregnancies at three London Hospitals and the results for the first 14 789 births have been presented. The antibody carriage rate was 56% (58% in the Griffiths & Baboonian series), although 90% of Asian women were positive. Throat swabs were cultured from all the babies and 42 (3 per 1000 births) were found to have congenital CMV infection; only two babies had problems at birth. All infected children, together

Antiviral Properties of the HIV-1 Proteinase Inhibitor RO 31-8959:

The peptide derivative Ro 31-8959 has been shown to be a potent inhibitor of HIV proteinase with an IC50 of 2 × 10−9M, against HIV-1RF in acutely infected lymphoblastoid cells. This inhibition was not overcome by increasing the infectious dose or by extending the culture time. Similar antiviral activity was also obtained against HIV-2, SIV and several AZT-resistant strains of HIV-1. The time of addition of the inhibitor could be delayed for 22 h without significant loss of activity, supporting its mode of action as taking place late in the replication cycle of HIV-1. Ro 31-8959 also showed activity against chronically infected cells.