The study investigates the interaction of Staphylococcus aureus toxins, known as superantigens, with human T cells. Using a modified polymerase chain reaction (PCR) technique, the researchers determined that these toxins interact with specific Vβ elements of the human T-cell αβ receptor. The study found that different toxins preferentially stimulate T cells expressing particular Vβ elements, with each toxin stimulating a unique set of Vβ elements. This suggests that the ability to stimulate a large number of T cells is an evolutionarily conserved feature of these toxins. The findings also highlight the importance of T-cell stimulation in the mechanism of action of these toxins and provide insights into the mode of action of S. aureus toxins, which are significant contributors to morbidity and mortality in humans. The quantitative PCR method developed in this study may be useful for rapid estimation of human T-cell repertoires in various diseases.The study investigates the interaction of Staphylococcus aureus toxins, known as superantigens, with human T cells. Using a modified polymerase chain reaction (PCR) technique, the researchers determined that these toxins interact with specific Vβ elements of the human T-cell αβ receptor. The study found that different toxins preferentially stimulate T cells expressing particular Vβ elements, with each toxin stimulating a unique set of Vβ elements. This suggests that the ability to stimulate a large number of T cells is an evolutionarily conserved feature of these toxins. The findings also highlight the importance of T-cell stimulation in the mechanism of action of these toxins and provide insights into the mode of action of S. aureus toxins, which are significant contributors to morbidity and mortality in humans. The quantitative PCR method developed in this study may be useful for rapid estimation of human T-cell repertoires in various diseases.