Final answer:
Leukocidin is the toxin that causes lysis of white blood cells, and is produced by bacteria such as Staphylococcus aureus and Streptococcus pyogenes. It is classified as an exotoxin and is known for its damaging effects on immune cells.
Step-by-step explanation:
The toxin that causes lysis of white blood cells and other immune cells by damaging their cell membrane and is produced by pyogenic bacteria such as Staphylococcus aureus and Streptococcus pyogenes is leukocidin. These toxins are known to target leukocytes (white blood cells) and can contribute to the production of pus. Leukocidins are a class of exotoxins that act on the plasma membranes of targeted cells, causing lysis and cell death.
Specifically, some strains of S. aureus produce a leukocidin called Panton-Valentine leukocidin (PVL), which is known for causing severe skin infections and necrotizing pneumonia. It promotes inflammatory and cytotoxic effects which can damage tissues, particularly the lungs. Hence, the correct answer to the original question is d. Leukocidin.