Production of a human anti-CD4 monoclonal antibody with antiidiotype to anti-HIV type 1 glycoprotein 120.

Human anti-CD4 IgG antibodies from 3 HIV-1-infected patients were affinity purified and shown to inhibit HIV-1 binding and infection of HBP-T cells. Lymphocytes from patient A, whose anti-CD4 inhibited HIV-1 binding by 68% and infection by 72%, were cultured and transformed with EBV. A human monoclonal antiidiotype antibody against anti-HIV-1 gp120 (2B) was produced, which inhibited infection of HBP-T cells by 68% at 1 microgram/ml. Mice were immunized with 2B to determine whether this anti-CD4 could be an internal image antiidiotype against anti-HIV-1 gp 120 (Ab1). Two mice produced antisera reactive with rgp120 on ELISA, whereas immunization with normal IgG produced minimal reactivity compared to unreactive normal mouse sera. However, immunoblot competition studies in which affinity-purified anti-HIV-1 gp120 (Ab1) bound to the gp120 band on nitrocellulose strips in the presence of 2B demonstrated enhancement of signal (i.e., binding of Ab2 to Ab1), rather than inhibition of Ab1 binding. Thus 2B is not an internal image of the paratope of anti-HIV-1 gp120 but yet it is capable of inducing an antibody against rgp120. This indicates that the anti-CD4 (Ab2) does bind to the binding site of Ab1, but not as a complete internal image. These data indicate the production of a human monoclonal antiidiotype antibody that inhibits binding of HIV-1 to CD4 and induces the production of antibody against HIV-1 gp120, without being an internal image antiidiotype (Ab2 beta).

Human megakaryocytes have a CD4 molecule capable of binding human immunodeficiency virus-1.

Most human megakaryocytes (MGKs) express the CD4 antigen on their surface. Approximately 25% have a CD4 receptor density comparable to that of CD4+ T cells (Basch et al, Proc Natl Acad Sci USA 87:8085, 1990). In these studies, we show: (1) the presence of mRNA for CD4 in human MGKs; (2) the binding of human immunodeficiency virus-1 (HIV-1) to human MGKs; (3) the inhibition of binding by anti-CD4 (Leu3a) antibody or rCD4; (4) the infection of a human MGK line, CHRF-288 with HIV-1; and (5) inhibition of infection with anti-CD4. Human MGKs have mRNA for CD4 as shown by in situ hybridization with an RNA probe synthesized from a 3-kb cDNA sequence of plasmid pSP65.T4.8 containing the full-length CD4 sequence. MGKs (23% +/- 17%) bound HIV-1, as determined by anti-gp120 and anti-CD41 staining. Binding to human MGKs could be inhibited 55% to 75% with anti-CD4 or rCD4, respectively. Infection of a CD4+ MGK line (CHRF-288) could be accomplished with HIV-1, as determined by proviral DNA polymerase chain reaction and p24 production. Preincubation with anti-CD4 inhibited apparent proviral DNA infection by 100% and p24 production by 65% to 70%. Thus, human MGKs have a CD4 receptor capable of binding HIV-1. Using this receptor, HIV-1 can infect cells representative of the MGK lineage.

B-cell subsets and platelet counts in HIV-1 seropositive subjects.

A subset of B lymphocytes positive for the CD5 antigen have been implicated in several autoimmune disorders. To investigate their role in human immunodeficiency virus type 1 (HIV-1) infection, we studied peripheral-blood B and T lymphocytes from HIV-1-positive patients with (n = 13) and without (n = 18) thrombocytopenia, 8 patients with classic autoimmune thrombocytopenia, and 16 healthy controls. The proportion of CD5-positive B cells was significantly higher in the HIV-1-positive thrombocytopenic patients than in the healthy controls, as a result of both higher numbers of CD5-positive B cells and lower numbers of CD5-negative B cells. Platelet count was positively correlated with CD5-negative B-cell count (r = 0.6, p less than 0.001) and negatively correlated with proportion of B cells that were CD5 positive (r = -0.5, p less than 0.01) among the HIV-1-positive patients. The high concentrations of IgM-containing immune complexes in HIV-1-positive patients with autoimmune disorders may be due to changes in the CD5-positive B-cell subset.

Internal-image anti-idiotype HIV-1gp120 antibody in human immunodeficiency virus 1 (HIV-1)-seropositive individuals with thrombocytopenia.

Anti-CD4 antibody was found in 30% of human immunodeficiency virus (HIV-1)-seropositive thrombocytopenic patients compared with 5% of nonthrombocytopenic seropositive patients (chi 2 = 21.7, P less than 0.001) and was shown by the following observations to contain internal-image anti-idiotype antibody (Ab2) directed against the antibody (Ab1) to gp120, the HIV-1 envelope glycoprotein that binds to CD4: (i) affinity-purified anti-CD4 (Ab2) bound to affinity-purified anti-HIV-1gp120 (Ab1) on solid-phase radioimmunoassay, and binding could be blocked by recombinant CD4 (rCD4) as well as recombinant gp120 (rgp120); (ii) F(ab')2 fragments of Ab1 inhibited the binding of Ab2 to rCD4; (iii) Ab2 inhibited the binding of Ab1 to HIV-1 beads; (iv) Ab2 inhibited the binding of Ab1 to gp120 on immunoblot; (v) Ab2 bound to the CD4 receptor on a CD4-bearing T-cell line, H9; (vi) Ab3 (anti-rgp120) could be produced in vivo by immunizing mice with Ab2, and binding of Ab3 to rgp120 could be blocked with rCD4; and (vii) three different Ab2 preparations bound to two different homologous Ab1 preparations. Ab1 or Ab2 alone did not bind to platelets, whereas the idiotype-anti-idiotype complex did bind to platelets in a concentration-dependent manner. Binding of the internal-image complex was 10-fold greater than that of a non-internal-image Ab1-Ab2 complex composed of anti-HIV-1gp120 and anti-anti-HIV-1gp120. Thus, patients with HIV-1 thrombocytopenia contain internal-image idiotype-anti-idiotype complexes that could be affecting CD4 cell number or function, inhibiting HIV-1 binding to CD4 cells or contributing to HIV-1 thrombocytopenia.

Improving the cost-effectiveness of AIDS health care in San Juan, Puerto Rico.

In an era of decreasing availability of funds and increasing demand, the AIDS epidemic threatens to overwhelm health-care services in some countries. We describe a comprehensive model for the treatment of AIDS in San Juan, Puerto Rico, and compare it with traditional hospital-based services. Given the existing allocation of funds, the comprehensive model emphasised prevention, education, surveillance, early detection, and outpatient care to reduce hospital care. In 1987, the last year of the traditional system, there were 95 admissions of AIDS patients to hospital, and in 1988, the first year of the comprehensive model, there were 100 admissions. The mean length of stay of AIDS inpatients was reduced from 22.3 days in 1987 to 11.3 days in 1988, a 46.8% reduction (p = 0.001). The annual mean (SE) cost of inpatient care per AIDS patient fell from $15,118 (1699) in 1987 to $3869 (659) in 1988. Savings were used to improve non-hospital services, including outreach, education, emergency and outpatient care, laboratory and epidemiological services, and research, and to introduce an employee incentive scheme. Management strategies that reduce the length of inpatient care and provide less costly treatment alternatives can improve AIDS health care in developing nations.

Expression of CD4 by human megakaryocytes.

The CD4 antigen, which serves as the receptor for human immunodeficiency virus type 1 (HIV-1) on T cells, has been detected on human megakaryocytes. Recent evidence of impaired thrombopoiesis in HIV-1-related thrombocytopenia suggested that these cells could be directly infected by the virus and prompted a search for a receptor on megakaryocytes of normal subjects that could permit entry of HIV-1. Bone marrow specimens from uninfected normal control subjects were centrifuged over Ficoll-Hypaque (1.077 g/ml) and analyzed by three-color analysis with a flow cytometer utilizing monoclonal antibodies against CD4 and a glycoprotein present on the surface of megakaryocytes and platelets (GPIIb/IIIa; CD41), as well as 7-aminoactinomycin D, a stain for DNA. Cells presumed to be megakaryocytes were identified by having a DNA content greater than tetraploid and staining brightly with anti-CD41. Approximately 0.4% of the nucleated cells of the marrow met these criteria. Twenty-five percent of these megakaryocytes stained as brightly as CD4+ T cells. Several clones of antibody recognizing different epitopes of the CD4 molecule gave similar results. Platelets were CD4-. Staining of megakaryocytes with anti-CD4 was confirmed by direct microscopic examination of Percoll-gradient-enriched megakaryocytes employing two-color (CD4-phycoerythrin and CD41-fluorescein) immunofluorescence analysis and phase-contrast microscopy. The proportion of double-labeled cells among 112 phase-contrast-identifiable megakaryocytes from five bone marrow specimens varied between 20% and 26% with a mean and SD of 22% +/- 2.5%. Thus some human megakaryocytes express CD4 on their surface that should be capable of binding the HIV-1 gp120 envelope protein. This could serve as a portal of entry for HIV-1.

Effect of penicillin and spectinomycin given for urethritis and cervicitis with Neisseria gonorrhoeae: high prevalence of penicillin-resistant isolates.

Efficacy of single-dose spectinomycin (TRO: 2 g intramuscularly) was compared with that of aqueous procaine penicillin G (APPG:4.8 x 10(6) units) plus 1 g of probenecid for treatment of gonococcal urethritis and cervicitis. Cure rates of the 210 patients who received TRO and 190 patients who received APPG were 97.6% and 91.1%, respectively. MICs of antibiotics were determined using the agar dilution method. Those isolates with MICs of APPG of less than 1.0 microgram/ml had low failure rates (2.9%), while strains with increased resistance to APPG (MICs greater than or equal to 1.0 microgram/ml) had higher failure rates (24%). Treatment failures seen with TRO were not correlated to isolates with the higher MICs. Clinical results suggest TRO could be given for treatment of genital gonorrhoea in Puerto Rico due to the high prevalence of both chromosomally-mediated penicillin-resistant Neisseria gonorrhoeae (20%) and penicillinase-producing Neisseria gonorrhoeae (7.5%) strains and the high rate of failure seen with the use of APPG.

Inapparent genital herpes simplex infection in women attending a venereal disease clinic.

The purpose of this study was to determine the prevalence of asymptomatic genital infection with herpes simplex virus in women attending a venereal disease clinic in Puerto Rico. Genital samples were obtained from 123 consecutively enrolled patients. Vero cells were used for viral isolation; isolates demonstrating cytopathic effect were stored at -70 C and were typed by use of monoclonal antibodies. Herpes simplex virus was isolated from six patients, three of whom were free of any possible complaint that might be associated with a genital herpes virus infection. One patient was diagnosed as having herpetic cervicitis, and the remaining two were clinically diagnosed as well as laboratory confirmed cases of genital herpes. Virus isolated from all six women was identified as herpes simplex virus type 2. Thus the prevalence of laboratory confirmed genital herpes infection in women attending this clinic was 4.9% (6/123). Inapparent virus infection was detected in 2.5% (3/120) of the patients.