Question

1. Post-exposure prophylaxis for rabies includes shots of HRIG (human rabies immune globulin) and rabies vaccine. The HRIG provides ________________ whereas the vaccine promotes the development of _______________.

Multiple Choice

• artificial passive immunity; natural active immunity

• artificial passive immunity; artificial active immunity

• natural passive immunity; artificial passive immunity

• artificial active immunity; artificial passive immunity

• artificial active immunity; natural active immunity

2. Primary and secondary antibody response differ in all the following ways, except

Multiple Choice

• IgG production predominates in secondary responses.

• the lag period between antigen stimulation and antibody response is shorter in the secondary response.

• the rate of antibody production is faster in secondary responses than in primary responses.

• primary responses are active whereas secondary responses are passive.

MICROBIOLOGY

Answer 1

1. Active immunity is the immunity produced in the body due to response to an antigen. It is natural active immunity when the body is naturally infected with a pathogen. Artificial active immunity is when the body is injected with attenuated or dead pathogens, which generates immunity. This is via vaccines. Passive immunity is due to antibodies that are injected or naturally present. Transfer of antibodies from mother to baby during pregnancy is natural passive immunization. Artificial passive immunization is when antibodies are injected against a pathogen in to human body.

The Rabies vaccine is therefore artificial active immunization. The rabies vaccine is killed virus. The administration of HRIG is artificial passive immunization as antibodies are artificially injected.

Right Choice: artificial passive immunity; artificial active immunity.

2. Primary antibody response is the response to an antigen when it is first encountered by immune system. IgM is the predominant antibody first formed, which is then followed by serum IgG or mucosal IgA antibody. In the second immune response, there is rapid immune response to reencountering the same response. It is mostly an IgG response, except IgA or IgE in some circumstances. In primary response, the lag period between stimulation and antibody response to antigen is 4-7 days while in secondary response, the lag phase is nonexistent or shorter period of 1-3 days. More plasma cells are produced in secondary response as there are more memory cells. Hence, there will be faster antibody response in secondary response as compared to primary response, resulting in shorter lag phase. As both primary and secondary responses are to exposure to antigen, these responses are active immune response. In passive immune response, there is either natural antibodies or antibodies from other sources are administered. Hence, there is no production of antibody in the organism that is showing the immune response.

Right choice: primary responses are active whereas secondary responses are passive.