Salivary detection of HIV-1 antibodies using recombinant HIV-1 peptides

A High-Throughput Assay for Circulating Antibodies Directed Against the S Protein of Severe Acute Respiratory Syndrome Coronavirus 2

More than 24 million infections with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were confirmed globally by September 2020. While polymerase chain reaction-based assays are used for diagnosis, there is a need for high-throughput, rapid serologic methods. A Luminex binding assay was developed and used to assess simultaneously the presence of coronavirus disease 2019 (COVID-19)-specific antibodies in human serum and plasma. Clear differentiation was achieved between specimens from infected and uninfected subjects, and a wide range of serum/plasma antibody levels was delineated in infected subjects. All 25 specimens from 18 patients with COVID-19 were positive in the assays with both the trimeric spike and the receptor-binding domain proteins. None of the 13 specimens from uninfected subjects displayed antibodies to either antigen. There was a highly statistically significant difference between the antibody levels of COVID-19-infected and -uninfected specimens (P < .0001). This high-throughput antibody assay is accurate, requires only 2.5 hours, and uses 5 ng of antigen per test.

Evaluation and diagnostic usefulness of saliva for detection of HIV antibodies: A cross-sectional study

Background:

Use of saliva as a specimen for detection of antibodies to infectious agents has generated particular interest in AIDS research community since 1980s. HIV specific antibodies of immunoglobulin isotypes IgA, IgG, and IgM are readily found in salivary secretions.

Aim and Objectives:

In the present study, HIV specific antibodies were detected in saliva and serum samples of HIV patients by ELISA in confirmed HIV seropositive patients and efficacy of saliva was established in diagnosis of HIV.

Methods:

The 100 saliva and serum samples were collected from age and sex matched confirmed HIV seropositive subjects and 100 Healthy Controls without any infections. HIV antibodies were determined by enzyme-linked immunosorbent assay (ELISA) using Genscreen HIV 1/2 Kit.

Results:

The results were found to be 99% sensitive and 100% specific for saliva samples, while it was 100% sensitive and specific for serum samples.

Conclusion:

Saliva can be used as alternative to blood for detection of HIV antibodies as saliva collection is painless, non-invasive, inexpensive, simple, and rapid. Salivary antibody testing may provide better access to epidemic outbreaks, children, large populations, hard-to-reach risk groups and may thus play a major role in the surveillance and control of highly infectious diseases.

Salivary immunoglobulin A antibodies to gp41 in human immunodeficiency virus-seropositive patients: lack of correlation with disease progression

Mucous membranes are the main route of transmission of human immunodeficiency virus (HIV). Interestingly, some viral inhibitory activities have been found in saliva. The purpose of this study was to determine the level of salivary immunoglobulin A (IgA) antibodies to gp41 in HIV+ patients at various disease stages to identify whether gp41 was able to induce vigorous humoral responses. Unstimulated saliva samples were obtained from three groups of subjects (n=37): group A (HIV-), group B (HIV+, CD4+ <200/mm3), and group C (HIV+, CD4+ >200/mm3). IgA antibody levels to purified gp41 were determined by enzyme-linked immunosorbent assay (ELISA). Western blot analyses were performed using HIV+ saliva to confirm IgA reactivity to gp41. ELISA demonstrated that HIV+ subjects had higher IgA antibody to gp41 than HIV- individuals. No significant differences were noted between HIV+, CD4+ <200/mm3 and CD4+ >200/mm3 subjects. High (81.25%) IgA reactivity to gp41 was demonstrated by Western blotting of saliva from all HIV+ individuals. In conclusion, gp41 responses are important in the HIV disease process, as indicated by the high IgA levels and gp41 reactivity in saliva of HIV+ patients.

HIV topic update: oro-genital transmission of HIV

Several viruses, including the human immunodeficiency virus (HIV), can be found in blood and many body fluids including saliva, and are transmissible sexually across genital and particularly anal mucosae. A persisting concern has been the question of transmission of HIV by oral sexual practices. This review discusses the evidence for oro-genital transmission of HIV, detailing the presence and infectivity of HIV in genital fluids and saliva, the case reports and epidemiology of oro-genital HIV transmission, and the evidence from animal studies. Oral intercourse is not risk-free. The evidence suggests that the risk of HIV transmission from oro-genital sexual practices is substantially lower than that from penile-vaginal or penile-anal intercourse, that exposure to saliva presents a considerably lower risk than exposure to semen, and that oral trauma and ulcerative conditions might increase the risk of HIV transmission.

A simple saliva-based test for detecting antibodies to human immunodeficiency virus

This study was performed to determine the feasibility of using saliva as a diagnostic medium for the detection of antibodies to human immunodeficiency virus type 1 (HIV-1) and HIV-2 under nonlaboratory conditions and to evaluate the performance characteristics of such a test. We developed for this purpose a self-contained kit (Saliva. Strip [ST]), which combines the collection and processing, as well as the analysis, of the specimen. The kit's performance was evaluated in a blinded study. Saliva collection was facilitated with a specially designed device that contains a sample adequacy indicator, and immunochromatography test strips were used for the analysis. A total of 1,336 matched serum and saliva specimens (684 reactive and 652 nonreactive specimens) were tested. We tested sera using an enzyme immunoassay (EIA) and a rapid strip test. Sera reactive in one of the assays were also analyzed by Western blotting. Sensitivity and specificity were 99.4 and 99.4%, respectively, for ST, 100 and 99.1%, respectively, for EIA, and 99.7 and 100%, respectively, for the serum strip test. The saliva test performed well when HIV-2-positive sera or a low-titer performance panel (HIV-1) of serum or plasma specimens were diluted (1:2,000) in nonreactive saliva. Because the methodology we present here uses a noninvasively obtained medium, the methodology may be suitable for use in the field where laboratory support and personnel are limited, such as community outreach programs, doctors' offices, surveillance studies, and community hospitals.

Clinical applications of two detection systems for HIV using saliva

The purpose of this research was to determine if the accuracy of HIV saliva and serum test results were influenced by changes in collection sites. In order to do so, serum and saliva samples were collected from 615 subjects in eight different geographic settings. The oral fluid collection/testing systems utilized were the Orapette SalivaCard HIV-1/HIV-2 antibody test (Trinity Biotech, Ireland) and the Omni-SAL/ImmunoComb II HIV 1 & 2 Saliva Test (Orgenics Ltd, Israel). For comparison, serum samples were tested by ELISA (Ortho) with reactive results confirmed via HIV-1 and HIV-2 Western blots (Biotech/Dupont, Institute Pasteur). The HIV serum and oral fluid collections were conducted in numerous test sites, which provided a great diversity in temperature, lighting and physical layout. The tests proved to be 99.8% and 100% specific, and both were 100% sensitive, regardless of the physical setting of the collections. While these systems are not currently available in the US, this study clearly demonstrates they can accurately be utilized in a variety of clinical settings, providing great promise for future applications.

Human submandibular saliva specifically inhibits HIV type 1

Studies from a number of laboratories have shown the presence of factor(s) in whole, parotid, and submandibular human saliva capable of inhibiting HIV-1 infectivity in vitro. Data from our laboratory suggested that the level of anti-HIV-1 activity is higher in submandibular than parotid or whole saliva. Previous results obtained with pooled submandibular saliva from seronegative individuals included a filtration step following saliva-virus interaction. In this article, we present data on the HIV-1 inhibitory activity of individual submandibular saliva samples collected from 15 donors. We show that although anti-HIV activity is quantitatively similar in most individuals (9 of 15), some (4 of 15) are much less active than others and some (2 of 15) lack inhibitory activity. We also show that for most individuals the level of anti-HIV inhibitor is similar with or without a filtration step. However, 2 of the 15 samples demonstrated activity only after filtration. The quantitative and qualitative anti-HIV activity of individual saliva samples appeared to reflect differences in the individual donors. We further show that the anti-HIV activity of submandibular saliva is demonstrated not only against laboratory strains of HIV-1 but is similarly active against three clinical HIV-1 isolates. In contrast, submandibular saliva had little effect on the infectivity of HIV-2 or SIV.

Evaluation of two novel immunoassays designed to detect HIV antibodies in oral fluids

The testing of oral fluid samples for the detection of HIV antibodies offers several advantages over the testing of blood. Our objective was to evaluate a new generation of rapid and simple assays designed specifically to detect HIV-1 and HIV-2 antibodies in oral fluids (saliva). Serum and oral fluid pairs were collected from 615 high- and low-risk individuals in the United States, Peru, and the ivory Coast. Two different oral fluid collection devices and rapid assay systems included: (1) the Orapette/SalivaCard HIV-1/ HIV-2 and (2) the Omni-Sal/ImmunoCcmb II HIV-1 and HIV-2. The corresponding serum pairs were analyzed by conventional ELISAs, and all reactive sera were confirmed with HIV-1 and HIV-2 Western blots. The results indicated a 100% sensitivity for both rapid oral fluid assays, including successful detection of HIV-2 antibodies. Specificities ranged from 99.8% to 100%. One sample produced a reactive result by the SalivaCard while being nonreactive by the other assays including the Western blots. Both assays performed excellently, indicating that antibodies to HIV can be detected reliably in oral fluids by simple and rapid assays. This combination of rapid testing technology and the use of easily collected oral fluid samples offers an efficient and accurate alternative to conventional testing and can be appropriately applied to a variety of testing situations for the laboratory diagnosis of HIV infection.

Oral fluid as a specimen for detection and confirmation of antibodies to human immunodeficiency virus type 1

Paired serum and oral fluid specimens (n = 287) were collected with the Omni-Sal device and were assayed for the presence of antibodies to human immunodeficiency virus type 1 (HIV-1). Enzyme immunoassays (EIAs)--Abbott 3A11, an Organon Teknika Corporation research-use-only test, and the Murex GACELISA--were used per the manufacturers' inserts or were modified slightly to accommodate the oral fluid specimens. Compared with serum Western blot (immunoblot) results, each EIA had a sensitivity of 100% and the specificities were 89.6% for the Abbott 3A11 EIA, 96.5% for the GACELISA, and 97.8% for the Organon Teknika Corporation EIA. Specificities based on specimens that were repeatedly reactive were 99.3% for all EIAs. A miniaturized Western blot technique used for confirmatory testing of both the serum and oral fluid specimens found 149 of the 287 samples to be HIV-1 antibody positive in both sample types. The Western blot banding patterns observed for the serum and oral fluid specimens were essentially identical. Immunoglobulin G concentrations were determined for all oral fluid specimens and ranged from < 0.5 to > 40.0 micrograms/ml. Immunoglobulin G concentrations did not correlate with the ability of any of the EIAs to detect HIV-1-specific antibody or with the ability of the modified Western blot to detect HIV-1 protein-specific antibodies.

Immunologic status in patients infected with HIV with oral candidiasis and hairy leukoplakia

Although numerous studies of oral manifestations associated with HIV have been reported, only a few refer to the correlation of these lesions with laboratory parameters. In this study we investigated the relationships between the two most common HIV-associated oral lesions, oral candidiasis and hairy leukoplakia, with the stage of the disease, circulating CD4+ cell counts, and the presence of anti-p24 antibodies in serum and stimulated whole saliva in 43 known HIV-1-infected persons. Although oral candidiasis and hairy leukoplakia were exclusively observed in subjects who were classified as Centers for Disease Control and Prevention group IV, only the prevalence of oral candidiasis is strongly associated with circulating CD4+ counts less than 200/mm3 (p < 0.02). The prevalence of oral candidiasis and hairy leukoplakia was significantly related to the absence of anti-p24 antibodies in serum (p < 0.01 and p < 0.01, respectively), but was only statistically significant for hairy leukoplakia in stimulated whole saliva (p < 0.02). The results suggest that oral candidiasis and hairy leukoplakia in correlation with immunologic status as indicated by low circulating CD4+ cell counts and the absence of anti-p24 antibodies in serum and the loss of secretory anti-p24 antibodies in subjects with hairy leukoplakia, may constitute prognostic markers for the progression of HIV-infection to AIDS. Our results also indicate that the absence of anti-p24 antibodies is not only influenced by the low levels of circulating CD4+ cells but probably by the presence of oral candidiasis or hairy leukoplakia as well.

Detection of anti-HIV antibodies in saliva

It is sometimes difficult in clinical practice to identify carriers of the AIDS virus. Such identification is of unquestionable value in oral pathology, both for determining the pathogenesis of certain lesions and for assessing their significance to the patient. We evaluated several commercially available diagnostic techniques for the detection of anti-HIV antibodies in serum, and examined the feasibility of adapting such techniques to tests on saliva. The technique chosen for experimental adaptation required only slight modifications for use with this medium. We compared the results obtained in serum from intravenous drug users with a western blot assay designed to detect p24 viral protein, against the findings with a test designed to detect salivary antibodies. The likelihood of cross-reactions in saliva containing high concentrations of other antiviral antibodies was also studied. The specificity and sensitivity of the modified saliva test were 100% and 96% respectively, and no cross-reactions were observed.