Racial and other characteristics of human T cell leukemia/lymphoma (HTLV-I) and AIDS (HTLV-III) in Trinidad.

Adult T cell leukaemia/lymphoma was first recognised as a clinical entity in southwest Japan. Subsequently the Caribbean has been found to be another area where the disease is endemic, and sporadic cases have been identified in different parts of the world. The human T cell leukaemia/lymphoma virus (HTLV-I) is causally related to adult T cell leukaemia/lymphoma. A subgroup of HTLV, designated HTLV-III, has recently been isolated from many patients with the acquired immunodeficiency syndrome (AIDS) and preAIDS, and there is now evidence that this variant is the primary cause of AIDS. This is the first report from Trinidad to describe 12 cases of adult T cell leukaemia/lymphoma and 14 of AIDS. All were in patients of African descent. No cases were seen in subjects of East Indian descent, who, like those of African descent, comprise as much as 40% of the population. West Indians of African descent may have increased susceptibility to infection with both HTLV-I and HTLV-III.     

Mixed-Backbone Oligonucleotides Containing Phosphorothioate and Methylphosphonate Linkages as Second Generation Antisense Oligonucleotide

Abstract

Antisense oligonucleotides are being studied as novel therapeutic agents. To further improve the properties of antisense oligonucleotides, we have synthesized phosphorothioate oligonucleotides containing methylphosphonate linkages at the 5′-end, the 3′-end, or in the center, and have evaluated the impact of these linkages on the biophysical properties, biological properties, and some of the safety parameters.     

Seroepidemiology of HTLV-III antibodies in a remote population of eastern Zaire.

A human retrovirus--human T cell lymphotropic virus-III (HTLV-III)--has recently emerged as the probable cause of acquired immunodeficiency syndrome (AIDS). In May 1984, 250 outpatients at a hospital in a remote area of eastern Zaire were surveyed for AIDS type illnesses and the prevalence of antibodies against HTLV-III determined by an enzyme linked immunosorbent assay using disrupted whole HTLV-III virus as the antigen. No clinical cases of AIDS were diagnosed among these patients. Overall, 31 (12.4%) had clearly positive ratios (greater than or equal to 5.0) and a further 30 (12.0%) had borderline ratios (3.0- less than 5.0). Western blots of serum samples from subjects with antibodies yielded bands consistent with HTLV-III as found in American patients with AIDS and members of groups at risk of AIDS. The prevalence of antibody was highest in childhood (p = 0.02); among adults prevalence rose slightly with age. HTLV-III antibodies were more common among the uneducated (p = 0.006), agricultural workers (p = 0.03), and rural residents (p = 0.006), but the Western blot bands were generally weak in this group. By contrast, one urban resident had strong bands. The relatively high prevalence of antibodies among the rural poor in this area of Zaire suggests that HTLV-III or a closely related, cross reactive virus may be endemic in the region. A different natural history of infection, perhaps in childhood, may also explain the findings.     

Polyadenylation of 35S RNA in vitro by a cytoplasmic particulate fraction from mouse myeloma.

An ATP incorporating activity was found to be associated with cytoplasmic particulate fractions prepared from MOPC-104E tumors (a mouse plasmacytoma). The product was shown to be poly(A) by its chromatography pattern on oligo(dT) cellulose columns, and the endogenous primers included a 35S RNA species as analysed by Cs₂SO₄ density centrifugation and polyacrylamide gel electrophoresis. The labeled poly(A) was estimated to have a chain length of 200 nucleotides by gel electrophoresis, and hydrolysis of the poly(A) yielded approximately 100 AMP residues for every adenosine residue.     

Phylogenetic associations of human and simian T-cell leukemia/lymphotropic virus type I strains: evidence for interspecies transmission.

Homologous env sequences from 17 human T-leukemia/lymphotropic virus type I (HTLV-I) strains from throughout the world and from 25 simian T-leukemia/lymphotropic virus type I (STLV-I) strains from 12 simian species in Asia and Africa were analyzed in a phylogenetic context as an approach to resolving the natural history of these related retroviruses. STLV-I exhibited greater overall sequence variation between strains (1 to 18% compared with 0 to 9% for HTLV-I), supporting the simian origin of the modern viruses in all species. Three HTLV-I phylogenetic clusters or clades (cosmopolitan, Zaire, and Melanesia) were resolved with phenetic, parsimony, and likelihood analytical procedures. Seven phylogenetic clusters of STLV-I were resolved with the most primitive (deeply rooted) divergence involving several STLV-I strains from Asian primate species. Combined analysis of HTLV-I and STLV-I revealed that neither STLV-I clusters nor HTLV-I clusters recapitulated host species specificity; rather, multiple clades from the same species were closer to clades from other species than to each other. We interpret these evolutionary associations as support for the occurrence of multiple discrete interspecies transmissions of ancestral viruses between primate species (including human) that led to recognizable phylogenetic clades that persist in modern species. Geographic concordance of divergent host species that harbor closely related viruses reinforces that physical feasibility for hypothesized interspecies virus transmission in the past and in the present.     

An integrin-binding N-terminal peptide region of TIMP-2 retains potent angio-inhibitory and anti-tumorigenic activity in vivo

Tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits angiogenesis by several mechanisms involving either MMP inhibition or direct endothelial cell binding. The primary aim of this study was to identify the TIMP-2 region involved in binding to the previously identified receptor integrin α3β1, and to determine whether synthetic peptides derived from this region retained angio-inhibitory and tumor suppressor activity. We demonstrated that the N-terminal domain of TIMP-2 (N-TIMP-2) binds to α3β1 and inhibits vascular endothelial growth factor-stimulated endothelial cell growth in vitro, suggesting that both the α3β1-binding domain and the growth suppressor activity of TIMP-2 localize to the N-terminal domain. Using a peptide array approach we identify a 24 amino acid region of TIMP-2 primary sequence, consisting of residues Ile43-Ala66, which shows α3β1-binding activity. Subsequently we demonstrate that synthetic peptides from this region compete for TIMP-2 binding to α3β1 and suppress endothelial growth in vitro. We define a minimal peptide sequence (peptide 8-9) that possesses both angio-inhibitory and, using a murine xenograft model of Kaposi's sarcoma, anti-tumorigenic activity in vivo. Thus, both the α3β1-binding and the angio-inhibitory activities co-localize to a solvent exposed, flexible region in the TIMP-2 primary sequence that is unique in amino acid sequence compared with other members of the TIMP family. Furthermore, comparison of the TIMP-2 and TIMP-1 protein 3-D structures in this region also identified unique structural differences. Our findings demonstrate that the integrin binding, tumor growth suppressor and in vivo angio-inhibitory activities of TIMP-2 are intimately associated within a unique sequence/structural loop (B-C loop).     

In vivo genetic variability of the human immunodeficiency virus type 2 V3 region.

The principal neutralizing epitope of the human immunodeficiency virus type 1 (HIV-1) lies between two invariant cysteines in the third variable region (V3) of the viral envelope (gp120), and its amino acid sequence varies among different HIV-1 isolates. HIV-2 carries an analogous amino acid sequence between two cysteines of the V3 regions, but its functional similarity with the HIV-1 principal neutralizing epitope is uncertain. We studied the degree of genetic variation of the HIV-2 V3 region in fresh blood samples from 12 HIV-2-seropositive individuals from Guinea-Bissau. Polymerase chain reaction was used to amplify viral fragments of 465 bp containing the V3 region from cellular DNA. Nucleotide sequence analysis of the entire envelope fragment from each patient revealed that the degree of variation among field isolates of HIV-2 is comparable to that observed in the analogous region of HIV-1. Most of the HIV-2 isolates studied were highly related, suggesting the existence of a limited number of different viral strains in the cohort studied. Thus, the HIV-2 and HIV-1 V3 regions vary to a similar degree and may also have analogous functions.     

Influences of related retroviruses on lymphocyte functions

The human immunodeficiency virus (HIV-1) is known to be profoundly immunosuppressive [Spickett and Dalgleish (1988) Clin. Exp. Immunol. 71, 1]. In this communication, we have studied the influences of HIV-1 (BH10), HIV-2 (LAV-2) and STLV-3 on B and T cells from healthy volunteers. B lymphocytes were found to differentiate into immunoglobulin secreting cells in response to stimulation by proteins of HIV-1 and LAV-2, but not by STLV-3. This response was obtained at protein concentrations of 0.05-0.005 micrograms/ml and was T cell dependent. IgM secretion was induced only by HIV-1 in the EBV-transformed B cell line SKW 6.4. At higher concentrations all three retroviral preparations had inhibitory influences on functions of B as well as T lymphocytes. B cell differentiation was maximally inhibited by HIV-1 and LAV-2 when these proteins were added concurrently to cultures with the polyclonal B cell activators pokeweed mitogen or Epstein-Barr virus. Tetanus antigen-specific T cell lymphoproliferation was inhibited by all retroviral proteins. These findings suggest that related retroviruses differ in their capacity to influence normal immune responses.