Non-specific host defence that exists prior to the exposure to an antigen is called

Options

A. acquired immunity
B. passive immunity
C. innate immunity
D. active immunity

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the type of non-specific host defense that exists before exposure to an antigen. This means we are looking for a defense mechanism that is innate and does not require prior exposure to any pathogens.

2. **Identifying the Options**: The options provided are:
- Acquired immunity
- Passive immunity
- Innate immunity
- Active immunity

3. **Analyzing Each Option**:
- **Acquired Immunity**: This type of immunity develops over time and requires exposure to specific antigens. It is not present at birth, so it is incorrect.
- **Passive Immunity**: This involves the transfer of antibodies from one individual to another, providing temporary protection. It also requires prior exposure to an antigen, making it incorrect.
- **Innate Immunity**: This is the body's first line of defense that is present from birth. It does not require previous exposure to pathogens and acts against all types of pathogens in a non-specific manner. This option fits the criteria of the question.
- **Active Immunity**: This involves the production of antibodies in response to exposure to an antigen. It is developed after exposure, so it is also incorrect.

4. **Conclusion**: Based on the analysis, the correct answer is **Innate Immunity**. This type of immunity is non-specific and exists prior to any exposure to antigens.

**Final Answer**: Innate Immunity

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