Given the task definition and input, reply with output. In this task, you are given a sentence. You are expected to write the name of the organism substances in the body mentioned in the input. Although there might be several correct answers, you need to write one of them.

Bacterial killing was normal in the two patients studied , and chemotaxis was diminished in response to zymosan - activated plasma and to high concentrations of chemotactic peptides in the patients studied .
plasma