You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Type of receptor present on T-cells are: and explain in detail?
Helper T cells 

Carries CD4 marker.
Helps or induces immune responses.
Recognize antigen in association with class II MHC.
Macrophages are activated to kill intracellular microorganisms by secreting cytokines.

Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:127