Human Immunodeficiency Virus-infected Men Research Articles

Changes in systemic gonadal and adrenal steroids in asymptomatic human immunodeficiency virus-infected men: relationship with the CD4 cell counts.

Serum sex hormone-binding globulin (SHBG), testosterone, non-SHBG-bound testosterone, androstenedione, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and cortisol were measured in 58 homosexual men seropositive for human immunodeficiency virus (HIV), all clinically asymptomatic (Centers for Disease Control 1993 classification stage A). The HIV patients were divided into four groups according to the CD4 lymphocyte count--group 1 (more than 500/microliters, N = 14), group 2 (between 350 and 500/microliters, N = 16), group 3 (between 200 and 349/microliters, N = 22) and group 4 (less than 200/microliters, N = 6)--and compared with 11 antibody-negative men as controls. The SHBG levels were significantly increased in groups 1, 2, 3 (p < 0.01) and 4 (p < 0.05) compared with controls, with no differences between groups of patients. Compared with controls, testosterone concentrations were significantly lower in group 4 (p < 0.05) and non-SHBG-bound testosterone levels were significantly lower in groups 1 (p < 0.05), 2 (p < 0.01), 3 (p < 0.001) and group 4 (p < 0.001); DHT and androstenedione levels were significantly lower in group 4 (p < 0.05) and DHEA levels were significantly lower in group 2, group 3 (p < 0.01) and group 4 (p < 0.05) than in controls. Cortisol levels were significantly increased in groups 1 and 4 (p < 0.05) and FSH and LH concentrations were not significantly higher in HIV-infected men than in controls. Also, the DHEA, androstenedione, non-SHBG-bound testosterone and DHT levels were correlated with CD4 cell counts, showing that hypogonadism occurs as the CD4 lymphocytes decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal patterns of feline immunodeficiency virus transcripts in peripheral blood cells during the latent stage of infection

We have investigated the in vivo state of feline immunodeficiency virus (FIV) transcription in peripheral blood mononuclear cells (PBMC) of chronically FIV-infected, asymptomatic cats. FIV was detected in a high percentage of PBMC but not in the plasma of these cats. By quantitative reverse transcription-PCR (RT-PCR) analysis. FIV transcriptional status in the PBMC was characterized by extremely low or undetectable levels of unspliced or singly spliced mRNAs and predominantly multiply spliced mRNAs. Upon stimulation in vitro, however, the larger mRNA species and infectious virus production were rapidly induced in the PBMC. Furthermore, we demonstrated that viral production was induced in association with differential increases in the levels of each multiply spliced mRNA coding for FIV regulatory proteins. From these results, we suggest that replication of FIV is blocked at an early stage of gene expression in vivo, as described in asymptomatic human immunodeficiency virus (HIV) -infected patients, and that FIV infection in cats may be a useful model for clinical latency of HIV infection in man. Moreover, we propose that the replication of FIV in vivo may be controlled by the differential expression of each multiply spliced mRNA.

Testicular dysfunction in human immunodeficiency virus—infected men

This review pertains to gonadal function in men with human immunodeficiency virus (HIV) infection, who often exhibit clinical and biochemical evidence of hypogonadism. Hypogonadotropic hypogonadism appears to be the most commonly encountered abnormality, although complete anterior pituitary insufficiency and primary gonadal failure have been reported. Levels of sex hormone—binding globulin (SHBG) are either unchanged or increased. Plasma levels of estrogens, progesterone, androstenedione, dehydroepiandrosterone sulfate (DHEA-S), and prolactin vary. Pathologically, except for involvement by opportunistic infections, no significant abnormality in the hypothalamic-pituitary area has been described, but evidence of orchitis is commonly present. The cause(s) of these abnormalities remains unclear. The possible factors leading to hypogonadism in HIV-infected men include HIV infection itself, opportunistic infections, chronic debilitating illness, and effects of cytokines on the hypothalamic-pituitary-gonadal axis. Further studies are needed to clarify the cause(s) of testicular dysfunction in HIV-infected men and its clinical significance, treatment, relevance to the progression of HIV infection, and influence on the immune system.

Mucosal transmission of simian immunodeficiency virus.

Although human immunodeficiency virus (HIV) is transmitted primarily by heterosexual contact very little is understood about the biology of heterosexual transmission of HIV. Epidemiological studies indicate that HIV is not efficiently transmitted by sexual contact. In fact many other sexually transmitted diseases (STDs) are more efficiently transmitted. For example, 22%–25% of individuals are infected by one exposure to Neisseriia gonorrheae (Holmes et al. 1970; Hooper et al. 1988), and hepatitis B virus is transmitted in 20%–30% of exposures (Judson 1981; Molsey 1975). In contrast, less than 15% of those monogamous individuals repeatedly exposed to an infected sexual partner become infected with HIV (Holmberg et al. 1989). It is estimated that for a single sexual contact, the infectivity of HIV is 0.3% (Hearst and Hulley 1988; Lawrence et al. 1990; Padian et al. 1987; Peterman et al. 1988). However, some individuals become infected after a single or a few sexual contacts (Peterman etal. 1988; Staskewski et al. 1987), while others remain uninfected despite hundreds of contacts (Lawrence et al. 1990). In the United States, HIV is apparently more efficiently transmitted from men to women than from women to men (Padian et al. 1987, 1991). Several cofactors have been identified which increase the risk of an individual acquiring HIV through heterosexual contact. Cervical ectopy, receptive anal intercourse, genital ulcer disease, and infection with other STDs are the most significant factors associated with HIV infection of women (Holmberg et al. 1988; Holmes and Kreiss 1988, Plummer et al. 1991) while the presence of an intact foreskin and genital ulcer disease of the penis are the risk factors most often associated with HIV infection in men (Cameron et al. 1989; Simonsen et al. 1988).

Circadian Rhythms of Circulating NK Cells in Healthy and Human Immunodeficiency Virus-Infected Men

Circadian Rhythms of Circulating NK Cells in Healthy and Human Immunodeficiency Virus-Infected Men

Pyrimethamine inhibits renal secretion of creatinine.

The mechanism of increased serum creatinine after administration of pyrimethamine and dapsone was evaluated for six healthy volunteers. Serum parameters, urine sediment, and clearances of creatinine, inulin, and para-aminohippurate were assessed prior to and 28 h after the ingestion of a single, combined dose of 100 mg of pyrimethamine and 200 mg of dapsone. In a second series, the same renal function tests were performed for nine human immunodeficiency virus-infected men before and after 1 month of prophylactic treatment with a weekly dose of 75 mg of pyrimethamine and 200 mg of dapsone to evaluate sustained effects on renal function. Serum creatinine increased within 28 h from 81 +/- 14 to 102 +/- 16 mumol/liter (P = 0.002) in the healthy volunteers. Blood urea nitrogen, beta 2-microglobulin, and urine remained normal. Creatinine clearance decreased from 125 +/- 27 to 91 +/- 26 ml/min (P < 0.02) without changes in inulin clearance. The effect was reversible within 21 days and attributable to pyrimethamine, as determined by administration of each drug alone. The sustained effect of four doses of pyrimethamine and dapsone in human immunodeficiency virus-infected patients consisted of an analogous rise in serum creatinine from 69 +/- 17 to 87 +/- 32 mumol/liter (P < 0.05). Both creatinine and inulin clearances, however, were unchanged, representing a new equilibrium between creatinine production and elimination at a higher level in serum. Pyrimethamine, thus, may reversibly inhibit renal tubular secretion of creatinine without affecting the glomerular filtration rate. This physiologic effect in pyrimethamine-treated patients must be differentiated from possible organ-related nephropathies.

Increased de novo hepatic lipogenesis in human immunodeficiency virus infection.

We measured de novo lipogenesis in human immunodeficiency virus (HIV) infected men using a newly developed stable isotope method. HIV-infected subjects with a history of weight loss (n = 17, mean weight loss 14.9 +/- 3.2 kg), asymptomatic HIV-seropositive subjects with normal CD4 T-cell counts (n = 7) and healthy HIV seronegative controls (n = 11) were studied. Hepatic lipogenesis was determined by infusion of [2-13C]-acetate, using the recently described xenobiotic probe technique with mass isotopomer analysis. Hepatic acetyl-coenzyme A enrichment was measured by high performance liquid chromatography/mass spectrometry of secreted sulfamethoxazole-acetate, with measurement of incorporation into very low density lipoprotein-fatty acids by gas chromatography-mass spectrometry. Circulating tumor necrosis factor (TNF), interleukin-1 (IL-1), interferon alpha (IFN alpha), insulin, and triglycerides were measured concurrently, and 7-day weighed food records were performed. De novo hepatic lipogenesis was increased 3- to 4-fold in HIV-infected subjects with weight loss compared to normal controls (P < 0.05 for palmitate and stearate in both overnight-fasted and fed states), and was also significantly increased in asymptomatic HIV seropositive subjects. Circulating TNF and IL-1 were not measurable in any subject (detection limit 2 pg/ml for IL-1 and 20 pg/ml for TNF). Serum IFN alpha was measurable in 11 out of 17 subjects with wasting and correlated significantly with de novo lipogenesis in overnight-fasted but not fed states. Serum IFN alpha was unmeasurable in asymptomatic HIV-infected subjects despite elevated lipogenic rates. Serum triglyceride concentrations were elevated in subjects with weight loss (2.09 +/- 0.28 mmol/L) and asymptomatic HIV-positives (1.34 +/- 0.34 mmol/L) in comparison to controls (0.67 +/- 0.08 mmol/L), and correlated with lipogenesis. Food intake correlated inversely with lipogenesis in the overnight-fasted state. We conclude that HIV infection is characterized by abnormal fat anabolism. This applies to subjects with reduced lean body mass and to asymptomatic HIV-positive subjects with normal T-cell counts. The former observation may have implications for the pathophysiology and treatment of the wasting syndrome. The latter observation is consistent with activation of the immune response and a state of viral nonlatency in early HIV disease.

Circadian rhythms of circulating NK cells in healthy and human immunodeficiency virus-infected men.

Antiviral immunity involves NK cells, which circulate rhythmically every 24 hours. We have investigated circadian and 12-hour rhythms in the peripheral count of circulating NK cells in 15 men infected with human immunodeficiency virus (HIV) and 13 healthy controls. We analyzed three phenotypes using double-labeling with monoclonal antibodies and flow cytometry assessment: CD3- CD16+, CD3-CD57+, and CD2+CD3-. A statistical validation of time-dependent differences was achieved if significance (p < 0.05) was validated both with analysis of variance and cosinor. The circadian rhythm had a similar asymmetric waveform for the three phenotypes and is homogeneous on an individual basis. The circulating NK cell count peaked in the early morning and was low at night. A circadian rhythm and a circahemidian harmonic characterized all phenotypes in healthy subjects. We considered two groups of HIV-infected men: those who were asymptomatic (eight) and those with acquired immune deficiency syndrome (AIDS) (seven). Circadian changes in NK cell count were similar in both subgroups and in healthy controls. The circadian pattern was also consistent among individual patients. Asymptomatic HIV-infected men (early-stage disease) exhibited more pronounced 12-hour rhythmicity than did patients with AIDS or controls. The circulation of NK cells does not appear to share the same synchronizer(s) as other circulating T- or B-lymphocyte subsets. Thus, HIV infection gradually abolished circadian rhythmicity in circulating T and B cells, whereas it did not disturb that in NK cells.

Insulin sensitivity and insulin clearance in human immunodeficiency virus-infected men

To test whether clinically stable human immunodeficiency virus (HIV) infection, like other infections, is associated with insulin resistance and increased insulin clearance, we measured the sensitivity to insulin and insulin clearance using the euglycemic insulin clamp technique in 10 clinically stable outpatients with symptomatic HIV infection (Centers for Disease Control [CDC] group IV) and 10 healthy controls. During administration of 0.8 and 4 mU insulin · kg −1 · min −1, HIV-infected men had 40% ( P < .02) and 83% ( P < .01) higher rates of insulin clearance when compared with healthy controls. Despite significantly lower steady-state insulin concentrations (42 ± 2 v 52 ± 4 μU/mL, P < .05, and 255 ± 17 v 392 ± 14 μU/mL, P < .001, patients v controls), patients and controls had similar total glucose uptake (7.99 ± 0.81 v 7.92 ± 0.44 mg · kg −1 · min −1 and 14.00 ± 0.81 v 13.65 ± 0.65 mg · kg −1 · min −1, patients v controls). In the postabsorptive state, no differences were found between patients and controls in insulin levels (7 ± 1 μU/mL in both) and endogenous glucose production (2.52 ± 0.07 and 2.24 ± 0.17 mg · kg −1 · min −1, respectively), but plasma glucose levels in the patients (5.02 ± 0.15 mmol/L) were significantly lower when compared with controls (5.46 ± 0.14 mmol/L, P < .05). The results indicate that HIV-infected men have increased rates of insulin clearance and increased sensitivity of peripheral tissues to insulin, which makes HIV infection unique with regard to glucose and insulin metabolism.

Safety and Pharmacokinetics of 566C80, a Hydroxynaphthoquinone with Anti-Pneumocystis carinii Activity: A Phase I Study in Human Immunodeficiency Virus (HIV)-Infected Men

A hydroxynaphthoquinone compound (566C80) has been shown to be effective in the prevention and treatment of murine Pneumocystis carinii pneumonitis. In a phase I study, five cohorts of four human immunodeficiency virus-infected men received 100, 250, 750, 1500, and 3000 mg of the compound orally once daily for 12 days. A sixth cohort received 750 mg three times daily for 5 days, then twice daily for 16 days. Evaluation included clinical, hematologic, and biochemical studies and the pharmacokinetics of 566C80. The only drug-related adverse effect was a maculopapular rash in one patient that resolved without discontinuation of the drug. With the largest dosage tested (3000 mg) the following pharmacokinetic measures were achieved: maximum plasma concentration, 39 micrograms/ml; time to maximum plasma concentration, 8.0 h; area under plasma concentration-time curve at steady state, 1088 h.micrograms/ml; plasma half-life, 51 h; and total plasma clearance, 4.09 l/h. Compound 566C80 offers promise as a new drug class for P. carinii pneumonia.

Increased resting energy expenditure in human immunodeficiency virus-infected men

Even in the absence of anorexia and malabsorption, weight loss is frequently observed in patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC). To investigate whether increased resting energy expenditure (REE) might be responsible for this weight loss, indirect calorimetry was performed in 18 human immunodeficiency virus (HIV)-infected men free of clinically active opportunistic infections for at least 2 months. Patients with AIDS (n = 11) or ARC (n = 7) had 9% higher rates of REE when compared with 11 healthy volunteers ( P < .05) with similar food intake and of the same body composition. The results obtained from patients with AIDS or ARC were identical. As no differences were found between patients and controls in plasma concentrations of catecholamines, thyroid hormones, cortisol, or tumor necrosis factor, except for lower concentrations of norepinephrine in the patients (mean ± SD, 233 ± 111 v 367 ± 125 ng/L, patients v controls, P < .01), this hypermetabolism is not explained by higher levels of these catabolic hormones. The results indicate that even in the absence of acute concomitant infections, increased REE may contribute to the weight loss in patients with AIDS or ARC.

Functional and phenotypic evidence for a selective loss of memory T cells in asymptomatic human immunodeficiency virus-infected men.

In addition to a well-documented depletion of CD4+ T helper cells in later stages of human immunodeficiency virus (HIV) infection, evidence has been provided for a specific unresponsiveness to triggering either by specific antigen in the context of autologous major histocompatibility molecules (self + X) or anti-CD3 monoclonal antibodies (MAb) in both CD4 and CD8 cells from asymptomatic HIV-infected individuals. In the present study we analyzed this unresponsiveness using mitogenic antibodies to distinct T cell membrane receptors. T cells from HIV-infected men who had normal numbers of CD4+ T cells responded poorly to activation signals via the CD3 membrane antigen in both accessory cell-dependent as well as accessory cell-independent culture systems. A similar low response was observed in an anti-CD2-driven system. In contrast, proliferation induced by anti-CD3, anti-CD2, or the phorbol ester Phorbol myristate acetate could be normally enhanced by anti-CD28 MAb. We demonstrated that this unresponsiveness is not due to a failure to induce early events required for activation, such as increased intracellular concentration of free calcium and activation of protein kinase C, but is caused by an imbalance between naive and memory T cells. In HIV-infected asymptomatic men, CD29+ memory T cells are selectively depleted which results in a poor responsiveness to self + X. These findings provide new insights that may have implications for our understanding of the immunopathogenesis of AIDS.

Oral ciprofloxacin versus ceftriaxone for the treatment of urethritis from resistant Neisseria gonorrhoeae in Zambia

Neisseria gonorrhoeae strains resistant to treatment with penicillin, tetracycline, and/or spectinomycin are increasing in prevalence in many parts of the world. In Zambia, 52% of N. gonorrhoeae isolates produced beta-lactamase in 1986. Few oral regimens have proven effective for treatment of resistant N. gonorrhoeae. We conducted a prospective, double-blind, randomized clinical trial of 250 mg of ciprofloxacin given orally versus 250 mg of ceftriaxone given intramuscularly for treatment of uncomplicated gonococcal urethritis in adult males. Two hundred men were enrolled and treated. The two groups were comparable in age (27.5 years), prevalence of latent syphilis (14 and 10%), and human immunodeficiency virus infection (32 and 38%). Of 165 patients with cultures positive for N. gonorrhoeae who returned for follow-up, ciprofloxacin cured 83 of 83 (100%), including 26 with penicillinase-producing N. gonorrhoeae (PPNG) and 21 with N. gonorrhoeae with chromosomally mediated resistance to multiple antibiotics (CMRNG), and ceftriaxone cured 81 of 82 (98.7%), including 30 with PPNG and 19 with CMRNG. Both treatment regimens were well tolerated. Chlamydia trachomatis in urethral exudate was found by direct fluorescent-antibody microscopic examination or by culture in 10 (5%) participants. All N. gonorrhoeae isolates were inhibited by ceftriaxone at 0.06 micrograms/ml, except one which was inhibited at 0.125 micrograms/ml, while ciprofloxacin inhibited all isolates at 0.03 micrograms/ml. Ciprofloxacin is a safe and effective therapy for uncomplicated gonococcal urethritis, including that caused by PPNG and CMRNG in human immunodeficiency virus-infected men.

Feline Immunodeficiency Virus (FIV) Infection in the Cat as a Model for HIV Infection in Man: FIV-Induced Impairment of Immune Function

To assess the value of feline immunodeficiency virus (FIV) infection as a model for human immunodeficiency virus (HIV) infection in man, we studied the impairment of certain immunological functions following natural or experimental FIV infection. Proliferative responses of peripheral blood mononuclear cells (PBMC) from symptomatic and asymptomatic cats after naturally or experimentally acquired FIV infection, induced by activation with the mitogens concanavalin A, pokeweed mitogen, or lipopolysaccharide or by stimulation with human interleukin-2 (IL-2), were significantly lower than the proliferative responses found with PBMC from noninfected control cats. Also IL-2 production levels of mitogen-activated PBMC from naturally infected symptomatic cats were significantly reduced. These data confirm that the pathogenesis of FIV infection in the cat, like HIV infection in man, is characterized by a serious malfunction of the immune system.

Bacterial Prostatitis in Patients Infected with the Human Immunodeficiency Virus

Bacterial prostatitis was diagnosed in 17 of 209 human immunodeficiency virus-infected men hospitalized from October 1985 to October 1987. A history of urogenital disease was found in 13 of 17 patients. Clinical signs of prostatitis were present in 16 of 17 patients, including fever in 13, urinary symptoms in 11 and tender prostate on rectal palpation in 7. Bacteriuria was found in 14 of the 17 patients. Prostatic ultrasound examination showed an abscess in 11 of 16 patients studied. Prostatitis was diagnosed at autopsy in 1 patient. Within 6 weeks after onset of antimicrobial therapy 9 of 13 patients were cured and 4 of 13 did not respond to therapy. Among the 7 patients followed for more than 2 months after the end of antimicrobial therapy 5 had relapse. The prevalence of bacterial prostatitis among human immunodeficiency virus-infected patients increased from 3 per cent in asymptomatic human immunodeficiency virus-infected patients to 14 per cent in patients with the acquired immunodeficiency syndrome.

Human Immunodeficiency Virus Infection Among Men With Sexually Transmitted Diseases: Experience From a Center in Africa

Heterosexual transmission of the human immunodeficiency virus (HIV) appears to occur readily in Africa but less commonly in North America and Europe. We conducted a case-control study among men attending a clinic for sexually transmitted diseases in Nairobi to determine the prevalence of HIV infection and the risk factors involved. HIV antibody was detected in 11.2 percent of 340 men who enrolled in the study. Reports of nonvaginal heterosexual intercourse and homosexuality were notably rare. Recent injections and blood transfusions were not associated with HIV infection. Travel and frequent contact with prostitutes were associated with HIV seropositivity. Men who were uncircumcised were more likely to have HIV infection (odds ratio, 2.7; P = 0.003), as were those who reported a history of genital ulcers (odds ratio, 7.2; P less than 0.001). A current diagnosis of genital ulcers was also associated with HIV seropositivity (odds ratio, 2.0; P = 0.028). Multivariate analysis revealed an independent association of genital ulcers with HIV infection in both circumcised and uncircumcised men. Uncircumcised men were more frequently infected with HIV, regardless of a history of genital ulcers. Our study finds that genital ulcers and an intact foreskin are associated with HIV infection in men with a sexually transmitted disease. Genital ulcers may increase men's susceptibility to HIV, or they may increase the infectivity of women infected with HIV. The intact foreskin may operate to increase the susceptibility to HIV.

Human immunodeficiency virus infection among men with sexually transmitted diseases. Experience from a center in Africa.

Heterosexual transmission of the human immunodeficiency virus (HIV) appears to occur readily in Africa but less commonly in North America and Europe. We conducted a case-control study among men attending a clinic for sexually transmitted diseases in Nairobi to determine the prevalence of HIV infection and the risk factors involved. HIV antibody was detected in 11.2 percent of 340 men who enrolled in the study. Reports of nonvaginal heterosexual intercourse and homosexuality were notably rare. Recent injections and blood transfusions were not associated with HIV infection. Travel and frequent contact with prostitutes were associated with HIV seropositivity. Men who were uncircumcised were more likely to have HIV infection (odds ratio, 2.7; P = 0.003), as were those who reported a history of genital ulcers (odds ratio, 7.2; P less than 0.001). A current diagnosis of genital ulcers was also associated with HIV seropositivity (odds ratio, 2.0; P = 0.028). Multivariate analysis revealed an independent association of genital ulcers with HIV infection in both circumcised and uncircumcised men. Uncircumcised men were more frequently infected with HIV, regardless of a history of genital ulcers. Our study finds that genital ulcers and an intact foreskin are associated with HIV infection in men with a sexually transmitted disease. Genital ulcers may increase men's susceptibility to HIV, or they may increase the infectivity of women infected with HIV. The intact foreskin may operate to increase the susceptibility to HIV.

Immunological study of the rectal mucosa of men with and without human immunodeficiency virus infection.

Biopsies of rectal mucosa were taken from 81 men and stained using cytochemical methods for B and T lymphocytes, T cell subsets, immunoglobulin containing plasma cells and mucosal mast cells. The patients studied included human immunodeficiency virus (HIV) infected and non-infected heterosexual and homosexual men, and homosexual men with rectal gonorrhoea. There were increased numbers of T lymphocytes in the lamina propria of the rectum in HIV infected individuals regardless of whether the infection had been acquired through anal intercourse or intravenous drug use. This increase resulted from a marked increase in the numbers of CD8+ suppressor T cells, there also being a reduction in the numbers of CD4+ helper T cells. In non-HIV infected men with rectal gonorrhoea there were increased numbers of CD8+ T cells but no significant difference in numbers of CD4+ cells. No difference was seen in numbers of CD4+ cells. No difference was seen in numbers of immunoglobulin containing plasma cells or mucosal mast cells between HIV infected and non-infected men.

Specific cellular immune response and neutralizing antibodies in goats immunized with native or recombinant envelope proteins derived from human T-lymphotropic virus type IIIB and in human immunodeficiency virus-infected men.

Animals immunized with native or recombinant envelope proteins from the human immunodeficiency virus (HIV, formerly referred to as human T-lymphotropic virus type III) human T-lymphotropic virus type IIIB and naturally HIV-infected men were assessed for neutralizing antibodies and cell-mediated immunity toward the virus. Immunization of rabbits or goats with the native external envelope glycoprotein gp120 or with corresponding recombinant proteins elicited strictly type-specific neutralizing antibodies. A broad, group-specific cellular immune response to gp120 and to three different HIV isolates was seen in goats immunized with the native gp120 but not in animals immunized with the nonglycosylated recombinant envelope proteins. In HIV-infected people, no T-cell response was seen, even though their T-cell response toward other foreign antigens was intact. The results show type- and group-specific epitopes on gp120, some of which may be of importance for the development of a vaccine against HIV infection.