Question

Active immunity may be produced by a. having a disease. b. receiving a vaccine. c. receiving gamma globulin injections. d. Both a and b are correct. e. Both b and c are correct.

Short answer

Based on our analysis, the correct answer is option d: Both a and b are correct. Active immunity may be produced by having a disease or receiving a vaccine.

Step-by-step solution

Understand active immunity

Active immunity is a type of immunity that occurs when the body produces its own antibodies to combat pathogens, such as bacteria and viruses. This can be achieved by natural infection or by vaccination.

Analyze option a: Having a disease

When a person gets infected with a pathogen and successfully recovers, their immune system learns to recognize the specific pathogen and produces antibodies to fight against it. This is an example of active immunity as the body has actively generated its defense mechanism. So, option a is correct.

Analyze option b: Receiving a vaccine

Vaccination involves introducing a weakened or inactivated form of the pathogen into the body. The immune system then recognizes the foreign substance and produces antibodies to target it. Since this process involves the body actively producing its own antibodies, option b is also correct.

Analyze option c: Receiving gamma globulin injections

Gamma globulin injections provide passive immunity by supplying the body with antibodies that have been obtained from another person or animal. Because these antibodies are not produced by the body itself, this option does not qualify as active immunity. Thus, option c is incorrect.

Analyze the combined options

We can now evaluate the combined options. Option d states that both a and b are correct, which is true, as having a disease and receiving a vaccine can both result in active immunity. Option e states that both b and c are correct, but this is false since receiving gamma globulin injections is not an example of active immunity.

Identify the correct answer

Based on our analysis, the correct answer is option d: Both a and b are correct. Active immunity may be produced by having a disease or receiving a vaccine.

Key concepts

Vaccination

Vaccination is a key tool in promoting active immunity. Through vaccination, a person is exposed to a weakened or inactive form of a pathogen. This harmless form is recognized by the immune system
and prompts the body to produce its own antibodies. These antibodies are proteins that help neutralize or destroy pathogens. The process may involve several doses over time to maintain effectiveness. Vaccines are responsible for the successful control

• Smallpox, a deadly disease, has been completely eradicated.
• Polio, once dreaded, has been significantly reduced worldwide.

Vaccines are powerful public health tools
designed to protect individuals and communities from infectious diseases.

Antibodies

Antibodies are specialized proteins produced by the immune system in response to antigens, which are components of pathogens. These proteins have a unique ability to recognize and bind to foreign molecules.
Once attached to the antigen, antibodies neutralize the threat directly or tag the pathogen for destruction by other immune cells. Antibodies are produced naturally after exposure to a pathogen
or artificially following vaccination. Types of antibodies include:

• IgG: Most common, provides long-term protection and is typically involved in secondary immune responses.
• IgA: Protects mucosal surfaces such as the gut, respiratory tract, and urogenital areas.
• IgM: Produced first in response to an infection.

Through the action of antibodies, the body is equipped to fend off repeated infections by the same pathogens.

Pathogens

Pathogens are harmful microorganisms such as bacteria, viruses, fungi, and parasites that can cause disease. They are capable of invading and multiplying inside the human body. Pathogens disrupt normal bodily functions, leading to symptoms of illness.
Human beings have evolved several mechanisms to combat these invaders, including the immune system's ability to recognize and respond specifically to pathogens. Pathogens vary in how they spread:

• Bacteria like Staphylococcus can infect cuts and wounds.
• Viruses such as the influenza virus spread through respiratory droplets.
• Fungi can affect the skin, such as Athlete's foot.

Understanding pathogens' methods of infection is crucial for developing vaccines and treatments
to protect against these diseases.

Passive Immunity

Passive immunity involves the direct transfer of ready-made antibodies into a person's system. These antibodies can come from another person or animal. This type of immunity is immediate but temporary,
as the body does not produce these antibodies itself. Passive immunity is often used for short-term protection in certain situations, such as:

• In newborns, where antibodies are transferred from the mother during pregnancy or through breast milk.
• Through antibody-containing blood products for patients exposed to specific pathogens.

Unlike active immunity, passive immunity does not provide long-lasting protection, as the transferred antibodies are eventually broken down
and removed from the body.

Immune System Response

The immune system response is a complex series of events that protect the body from infection. When a pathogen enters, the immune system recognizes it through antigens
and mounts a defense. This response involves several layers of protection:

• Innate Immune Response: The body's immediate response including physical barriers like the skin and immune cells like macrophages.
• Adaptive Immune Response: More targeted, involving T cells and B cells which produce antibodies specific to the pathogen.

The immune system has a unique ability to "remember" past infections due to memory cells, which allows for a quicker and stronger response upon re-exposure to the same pathogen.
This adaptive response is what makes vaccines effective in providing long-term immunity.