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Updated: Aug 9, 2026
In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function
Published on: October 16, 2013
A novel assay for assessment of HIV-specific cytotoxicity by multiparameter flow cytometry
Karina Godoy-Ramirez1, Barbro Mäkitalo, Rigmor Thorstensson
1Department of Immunology and Vaccinology, Swedish Institute for Infectious Disease Control, Sweden. karina.godoy@smi.ki.se
Insights
A new flow cytometry assay accurately measures HIV-specific cytotoxicity, offering higher sensitivity and reproducibility than traditional methods for evaluating immune responses.
Area of Science:
- Immunology
- Virology
- Flow Cytometry
Background:
- Assessing CD8(+) T-cell activity is crucial for understanding cellular immune responses to viral infections like HIV.
- Current methods for evaluating HIV-specific cytotoxicity have limitations.
Purpose of the Study:
- To introduce and validate a novel multiparameter flow cytometry assay for assessing HIV-specific cytotoxicity.
- To compare the performance of this new assay with established methods.
Main Methods:
- Target cells were labeled with CFSE and cultured with peptide-pulsed target cells and effector cells.
- Cytolysis was determined by quantifying viable target cells (CFSE(hi)PI(-)) using flow cytometry.
- The assay was validated against the 51Cr-release assay and IFN-gamma ELISpot.
Main Results:
- The flow cytometry assay showed strong correlation with the 51Cr-release assay (r=0.67) and ELISpot assay (r=0.66).
- The novel assay demonstrated significantly higher sensitivity (P < 0.05) and good reproducibility (CV, 7.7%) compared to the 51Cr-release assay.
- The assay effectively detected HIV-specific cytotoxic T-lymphocyte (CTL) responses.
Conclusions:
- This multiparameter flow cytometry assay is a specific and sensitive tool for detecting HIV-specific CTL.
- It is valuable for evaluating cytolytic activity in HIV vaccine trials and infected individuals, particularly for low-level responses.
Background:
Assessment of CD8(+) T-cell activity is of significant importance for the evaluation of cellular immune responses to viral infections, especially in HIV. We present a new assay for the assessment of HIV-specific cytotoxicity by multiparameter flow cytometry.
Methods:
Target cells, pulsed with peptide pools (Gag or Nef), were stained with 5- (and -6)-carboxyfluorescein diacetate succinimidyl ester (CFSE), cultured with specific or nonspecific effector cells, and finally stained with propidium iodide (PI). Determination of cytolysis is based on the enumeration of viable target cells (CFSE(hi)PI(-)) in the test sample (target and specific effector cells) as compared with that of the viable target cells in the control sample (target and nonspecific effector cells). The (51)Cr-release assay and IFN-gamma ELISpot were performed by standard procedures.
Results:
A comparison with the Cr-release showed that the two assays were strongly correlated (r = 0.67; P < 0.001) but the sensitivity of the flow cytometric assay was significantly higher (P < 0.05), and the reproducibility good (CV, 7.7%). Good correlation was also found with the ELISpot assay (r = 0.66; P < 0.01).
Conclusion:
This new assay provides both specific and sensitive results when employed for the detection of HIV-specific CTL and can be a valuable tool for the evaluation of cytolytic activity in vaccine trials or in HIV-infected subjects, especially if such responses are present at low levels.
