Which of the following types of antigens can be found on parasites within the body?

• A. Heterophile antigens
• B. Exogenous antigens
• C. Endogenous antigens
• D. Autoantigens

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the definitions of each antigen type. Exogenous antigens originate from outside the body, such as bacteria or viruses entering the body. Endogenous antigens are generated within the cells, often from normal cellular processes or viral infections. Autoantigens are normal body components that the immune system mistakenly targets in autoimmune diseases. Heterophile antigens are antigens that are shared by different species or organisms, including parasites.
2. Step 2: Recognize that parasites living within the body can express antigens that are not unique to them but are shared with other organisms, which are called heterophile antigens. These antigens can trigger immune responses because they are recognized as foreign.
3. Step 3: Compare the antigen types to the context of parasites. Since parasites are foreign organisms living inside the host, their antigens can be exogenous, but specifically, heterophile antigens are known to be present on parasites because they share antigenic determinants with other species.
4. Step 4: Conclude that among the options, heterophile antigens are the best fit for antigens found on parasites within the body, as they represent shared antigenic structures that can be recognized by the host immune system.
5. Step 5: Summarize that understanding the nature of antigen origin and their relationship to the immune system helps identify heterophile antigens as the type found on parasites inside the body.