Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Nov 17;20(1):269.
doi: 10.1186/s12985-023-02242-5.

In-house ELISA protocols for capsid p24 detection of diverse HIV isolates

Mariano A Molina  1 , Monique Vink  1 , Ben Berkhout  1 , Elena Herrera-Carrillo  2
Affiliations

In-house ELISA protocols for capsid p24 detection of diverse HIV isolates

Mariano A Molina et al. Virol J. .

Abstract

Background: The capsid p24 (CA-p24) antigen is a component of the viral capsid of human immunodeficiency virus (HIV) that has been commonly used for clinical diagnosis and monitoring of HIV infections in Enzyme-linked Immunosorbent Assays (ELISAs). Commercial CA-p24 ELISAs are widely used in research settings, but these kits are costly and have limited breadth for detecting diverse HIV isolates.

Methods: Commercial CA-p24 antibodies were used as capture and detection antibodies. Specific CA-p24 ELISAs were established with these antibodies and tested for the detection of HIV-1 isolates with the aim of developing in-house protocols to recognize HIV-1 infections in vitro for research purposes.

Results: Here we present four protocols for in-house ELISAs to detect HIV CA-p24 using commercial antibodies. The assays were able to detect the CA-p24 antigen of different HIV-1 isolates tested. Comparison between the protocols showed that these in-house ELISAs exhibit high specificity, sensitivity, and reproducibility for CA-p24 quantitation but their reactivity varied per HIV-1 isolate and subtype.

Conclusions: These optimized ELISA protocols represent valuable tools to investigate HIV-1 infections in research facilities at a lower price than commercial CA-p24 kits.

Keywords: Antibodies; Antigen; CA-p24; ELISA; HIV.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Schematic summary of CA-p24 ELISA protocols. Diagram of in-house CA-p24 ELISA protocols. Complete details of the protocols are described in the Results and Methods sections. ABR = Aalto Bio Reagents; ANG = Anogen; SB = Sino Biological; RND = R&D Systems
Fig. 2
Fig. 2
Analyses of CA-p24 antigen concentration on diverse HIV isolates. Twenty-two HIV-1 isolates were tested through ABR-, ANG-, SB-, and RND-CA-p24 ELISAs for detection of CA-p24 antigen. All ELISAs detected most of the isolates, except RND-CA-p24 ELISA which did not detect the 92UG029 isolate. PBS was used as negative control. Values were measured in two independent ELISA runs and error bars represent the standard deviation (SD). The CA-p24 axis is log-scaled in the graph. The list of HIV isolates can be found in Table 1. ABR = Aalto Bio Reagents; ANG = Anogen; SB = Sino Biological; RND = R&D Systems
Fig. 3
Fig. 3
Fold-change in CA-p24 detection of HIV-1 A/B isolates relative to ABR-CA-p24 ELISA. ANG-CA-p24 ELISA exhibits low reactivity for HIV-1 A and B subtypes when compared to ABR-CA-p24 ELISA. RND-CA-p24 ELISA shows acceptable reactivity for HIV-1 A and B subtypes when compared to ABR-CA-p24 ELISA, but low reactivity for the SI22 isolate. SB-CA-p24 ELISA displays good reactivity for HIV-1 A and B subtypes when compared to ABR-CA-p24 ELISA, but low reactivity for the LAI isolate. ABR = Aalto Bio Reagents; ANG = Anogen; SB = Sino Biological; RND = R&D Systems
Fig. 4
Fig. 4
Comparative reactivity towards HIV-1 isolates between assays as determined by Pearson’s r correlation. ANG-, SB-, and RND-CA-p24 ELISAs exhibit a significantly high correlation with ABR-CA-p24 ELISA. ANG-CA-p24 ELISA exhibits a significantly high correlation with RND-CA-p24 ELISA, whereas both RND- and ANG-CA-p24 ELISA show a low correlation with SB-CA-p24 ELISA. Concentrations of CA-p24 are displayed in ng/mL. ABR = Aalto Bio Reagents; ANG = Anogen; SB = Sino Biological; RND = R&D Systems
See this image and copyright information in PMC

References

    1. WHO. Data on the size of the HIV/AIDS epidemic 2021. https://www.who.int/data/gho/data/themes/hiv-aids/data-on-the-size-of-th....
    1. Menéndez-Arias L, Delgado R. Update and latest advances in antiretroviral therapy. Trends Pharmacol Sci. 2022;43(1):16–29. doi: 10.1016/j.tips.2021.10.004. - DOI - PubMed
    1. Dybul M, Attoye T, Baptiste S, Cherutich P, Dabis F, Deeks SG, et al. The case for an HIV cure and how to get there. Lancet HIV. 2021;8(1):e51–e58. doi: 10.1016/S2352-3018(20)30232-0. - DOI - PMC - PubMed
    1. Ng’uni T, Chasara C, Ndhlovu ZM. Major scientific hurdles in HIV vaccine development: historical perspective and future directions. Front Immunol. 2020;11. - PMC - PubMed
    1. Herrera-Carrillo E, Gao Z, Berkhout B. CRISPR therapy towards an HIV cure. Brief Funct Genomics. 2020;19(3):201–208. doi: 10.1093/bfgp/elz021. - DOI - PMC - PubMed