**Core Concept**
Measles vaccine is a live attenuated vaccine designed to protect against measles virus infection. It works by inducing both humoral and cellular immune responses, providing long-term immunity against the disease.

**Why the Correct Answer is Right**
The measles vaccine contains a weakened form of the measles virus, which triggers an immune response without causing the actual disease. This immune response involves the activation of CD4+ and CD8+ T cells, as well as the production of IgG and IgM antibodies, providing protection against future infections. The vaccine is typically administered in two doses, first at 9-12 months of age and a second dose at 4-6 years of age or at the time of school entry.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the measles vaccine does not contain a killed-virus component.
**Option B:** This option is incorrect as the measles vaccine is not a conjugate vaccine, which combines a polysaccharide antigen with a protein carrier to enhance immune response.
**Option C:** This option is incorrect as the measles vaccine does not require a booster dose every 10 years like the tetanus toxoid vaccine.

**Clinical Pearl / High-Yield Fact**
The measles vaccine is a crucial component of the measles, mumps, and rubella (MMR) vaccine, which also protects against mumps and rubella. The MMR vaccine is administered in two doses, first at 12-15 months of age and a second dose at 4-6 years of age or at the time of school entry.

**Correct Answer:** B.