What did Paul Ehrlich predict in immunology?

Correct Answer: A

Rationale: Paul Ehrlich predicted the existence of antibodies and their ability to bind toxins. He introduced the concept of the side-chain theory, proposing that cells have specific receptors (later known as antibodies) that can bind to toxins and neutralize them. This groundbreaking idea laid the foundation for modern immunology. Ehrlich's work was instrumental in understanding the immune response and paved the way for advancements in vaccine development and disease treatment. Choice B (Discovery of germ theory) is incorrect because it was proposed by Louis Pasteur and Robert Koch, not Paul Ehrlich. Choice C (Smallpox eradication) is incorrect as Ehrlich did not predict smallpox eradication. Choice D (Development of vaccines) is incorrect because while Ehrlich's work contributed to vaccine development, his specific prediction was about antibodies and their toxin-binding ability, not vaccines in general.

Correct Answer: C

Rationale: Correct Answer: C Rationale: 1. Innate immunity is rapid: It provides immediate defense against pathogens. 2. Innate immunity is non-specific: It reacts in the same way to all pathogens. 3. Adaptive immunity, on the other hand, is slower and pathogen-specific. 4. Adaptive immunity develops memory to provide long-lasting protection. Summary: A: Innate immunity does not develop memory; adaptive immunity does. B: Adaptive immunity may not always be functional due to various factors. D: Adaptive immunity requires activation through exposure to specific antigens.

Correct Answer: B

Rationale: The correct answer is B: Granzyme. Granzyme is the molecule released by NK cells that induces apoptosis in target cells. It enters the target cell through perforin, which creates pores in the target cell membrane. Cytokines are signaling molecules released by various immune cells but do not directly induce apoptosis. Antibodies are produced by B cells and do not induce apoptosis. Perforin aids in the delivery of granzyme but is not responsible for inducing apoptosis itself. Therefore, Granzyme is the correct choice for inducing apoptosis by NK cells.

Correct Answer: B

Rationale: The correct answer is B: Alternative pathway. This pathway involves properdin, Factor B, and Factor D. Properdin stabilizes the C3 convertase complex formed by Factor B and Factor D, leading to the amplification of the complement cascade. The other choices are incorrect because: A: Classical pathway is initiated by antigen-antibody complexes binding to C1q. C: Lectin pathway is activated by lectins binding to carbohydrates on pathogen surfaces. D: Terminal pathway involves the formation of the membrane attack complex.

Correct Answer: C

Rationale: The correct answer is C: Autoimmune diseases such as SLE. C1q is essential for the classical pathway of the complement system, which plays a crucial role in clearing immune complexes. A deficiency in C1q can lead to impaired immune complex clearance, resulting in the development of autoimmune diseases like Systemic Lupus Erythematosus (SLE). Choice A (Enhanced inflammation) is incorrect because a deficiency in C1q would actually lead to decreased inflammation due to impaired complement activation. Choice B (Reduced phagocytosis) is incorrect because phagocytosis is primarily mediated by the alternative pathway of the complement system, not the classical pathway involving C1q. Choice D (Increased cancer risk) is incorrect as C1q deficiency is not directly associated with an increased risk of cancer.