Following are some statements regarding the primary and secondary antibody response in humans. All the statements are correct except

Options

A. lag period (time between the introduction of antigen and appearance of antibodies in blood) in prmary response is longer than that is secondary response
B. predominant isotype produced in primary response is IgM while that in secondary response is IgG
C. primary antibodies have a higher affinity for antigen as compared to secondary antibodies
D. primary immune response is more quicker and intense than secondary immune response.

Explanation

To solve the question regarding the statements about primary and secondary antibody responses in humans, we will analyze each statement step by step to identify the incorrect one.

### Step-by-Step Solution:

1. **Understanding Primary and Secondary Immune Responses**:
- The primary immune response occurs when the immune system encounters a pathogen for the first time. This response takes longer to develop as the body needs time to recognize the pathogen and produce antibodies.
- The secondary immune response happens when the same pathogen re-enters the body. This response is quicker and more robust due to the presence of memory cells that remember the pathogen.

2. **Analyzing the Statements**:
- **Statement 1**: "The lag period in the primary response is longer than in the secondary response."
- **Analysis**: This statement is true. The primary response has a longer lag period because the immune system is encountering the pathogen for the first time.

- **Statement 2**: "The predominant isotype produced in the primary response is IgM while that in the secondary response is IgG."
- **Analysis**: This statement is also true. IgM is typically the first antibody produced during the primary response, while IgG is produced more abundantly during the secondary response.

- **Statement 3**: "Primary antibodies have a higher affinity for antigen as compared to secondary antibodies."
- **Analysis**: This statement is incorrect. In fact, secondary antibodies (IgG) generally have a higher affinity for the antigen due to affinity maturation that occurs during the secondary response.

- **Statement 4**: "A primary immune response is more quicker and intense than the secondary immune response."
- **Analysis**: This statement is false. The secondary immune response is quicker and more intense than the primary response due to the presence of memory cells.

3. **Identifying the Incorrect Statement**:
- Based on the analyses, the third statement is incorrect because primary antibodies do not have a higher affinity than secondary antibodies. The fourth statement is also incorrect, as the secondary response is quicker and more intense than the primary response.

### Final Answer:
The incorrect statement among the provided options is: **"Primary antibodies have a higher affinity for antigen as compared to secondary antibodies."**