Human Immune Response - IBDP SL\HL BIO

How does the body respond to antigens and their purpose in soliciting an immune response?

The body recognizes antigens as foreign substances and triggers an immune response involving the activation of lymphocytes, particularly T and B cells, which work to neutralize or eliminate the pathogens.

Outline the process of blood clotting in response to injury.

Blood clotting involves vascular spasm, formation of a platelet plug, and coagulation, which is driven by clotting factors like fibrinogen converting to fibrin to stabilize the clot.

What immune response occurs after immunization?

After immunization, the immune system generates a specific response by producing antibodies and activating memory cells, which provides immunity against future exposures to the same pathogen.

How are vaccines affected by mutations of pathogens?

Vaccines may become less effective if a pathogen mutates significantly, as changes in its antigens can prevent the immune system from recognizing it effectively.

How do bacteria and viruses respond to antibiotics?

Bacteria can be killed or inhibited by antibiotics, which target specific bacterial functions, while viruses do not respond to antibiotics as they rely on host cells for replication.

Outline the history of the development of antibiotics and how they work.

Antibiotics were discovered in the early 20th century, with penicillin being one of the first. They work by targeting bacterial cell walls, protein synthesis, or metabolism, specifically affecting prokaryotic cells but not eukaryotic cells.

How are B cells activated and what is their response?

B cells are activated by recognition of an antigen and the help of T helper cells, leading to their differentiation into plasma cells that produce antibodies.

What are the roles of plasma cells and memory cells in the immune system?

Plasma cells produce large quantities of antibodies that target specific antigens, while memory cells remain in the body to provide rapid responses upon future exposures to the same antigen.

Describe the production of monoclonal antibodies using hybridoma cells.

Monoclonal antibodies are produced by fusing an antibody-producing B cell with a myeloma cell to create a hybridoma, which can proliferate and produce identical antibodies targeting a specific antigen.

Differentiate between clotting factors, antibodies, plasma cells, memory cells, and immunoglobulins.

Clotting factors are proteins involved in blood coagulation, while antibodies are proteins produced by plasma cells, which are differentiated B cells, for immune defense. Memory cells are long-lived B cells that provide quick immune responses upon re-exposure to an antigen.

Explain the production of antibodies in the immune response.

Antibodies are produced by B cells after encountering an antigen, which through a complex process involving recognition, activation, proliferation, and differentiation into plasma cells, results in the secretion of specific antibodies.

Outline the various functions of monoclonal antibodies.

Monoclonal antibodies are used for diagnosis, treatment of diseases, drug delivery, and research due to their specificity for targeted antigens.

Explain the purpose of hybridoma cells in monoclonal antibody production.

Hybridoma cells are used to create a continuous supply of specific antibodies, combining the desirable traits of antibody-producing B cells with immortal myeloma cells.

How does the immune system respond to allergic symptoms and the role of histamines?

In response to allergens, the immune system releases histamines from mast cells, causing inflammation and allergy symptoms like itching, swelling, and mucus production.

Distinguish between HIV and AIDS.

HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, while AIDS (Acquired Immunodeficiency Syndrome) is the advanced stage of HIV infection characterized by a severely compromised immune system.

Explain the effects of HIV and AIDS on the immune system.

HIV leads to a gradual decline in CD4 T cells, weakening the immune system and increasing susceptibility to opportunistic infections and certain cancers, indicative of AIDS.

Differentiate between active and passive immunity.

Active immunity occurs when the body is exposed to an antigen and produces its own antibodies, while passive immunity involves the transfer of antibodies from another source, providing temporary protection.

Understand the graph of immune response and secondary responses.

The graph shows that during the primary immune response, antibody concentration rises slowly, whereas in secondary responses, antibody levels increase rapidly due to memory cells.

Define pathogen, antigen, antibody, innate immunity, and acquired immunity.

A pathogen is an organism causing disease, an antigen is a substance that triggers an immune response, an antibody is a protein that neutralizes pathogens, innate immunity is the non-specific first line of defense, and acquired immunity is the specific response developed after exposure.

Outline the process of response to antigens and clonal selection.

The immune response to antigens involves recognition, activation of lymphocytes, and clonal selection where specific B and T cells proliferate to provide an effective response.

Explain what antibodies are and their role in the immune response.

Antibodies are specialized proteins produced by B cells that identify and neutralize pathogens, playing a crucial role in the adaptive immune response.

What is a pathogen?

A pathogen is an organism that causes disease.

What forms the first line of defense against pathogens?

Skin and mucous membranes form the first line of defense against pathogens.

Outline the role of skin, sebaceous glands, and mucous membranes in the defense against pathogens.

Skin acts as a physical barrier, sebaceous glands produce oils that inhibit microbial growth, and mucous membranes trap pathogens and contain antimicrobial substances.

What are two benefits of blood clotting when skin is cut?

1. Prevents blood loss by sealing the wound. 2. Reduces the risk of infection by blocking the entry of pathogens.

What are two roles of platelets in the blood clotting cascade?

1. Platelets adhere to the site of injury to form a temporary plug. 2. They release clotting factors that initiate the coagulation process.

Describe the blood clotting cascade.

The cascade results in the rapid conversion of fibrinogen to fibrin by thrombin, involving platelets and clotting factors to form a stable clot.

What is the second line of defense against pathogens?

Phagocytic white blood cells are the second line of defense against pathogens.

What is the function of phagocytic white blood cells in defense against pathogens?

Phagocytic white blood cells engulf and digest pathogens, providing a non-specific immune response.

What is an antigen?

An antigen is a molecule that triggers an immune response.

List example antigen molecules.

Examples of antigen molecules include proteins, polysaccharides, and lipids on the surface of pathogens.

What is zoonosis?

Zoonosis is the transmission of diseases from animals to humans.

List three examples of zoonotic diseases.

Examples include rabies, Lyme disease, and West Nile virus.

Outline the difference between the ABO blood antigens.

The ABO blood group system consists of A antigens, B antigens, both A and B antigens, or neither (O type), determining blood type.

What are the four human ABO blood types?

The four human ABO blood types are A, B, AB, and O.

What are the consequences of mismatched blood transfusions?

Mismatched blood transfusions can cause agglutination (clumping of blood cells) and hemolysis (destruction of red blood cells), leading to serious health complications.

Define specific immune response.

Specific immune response is the targeted immune reaction against a specific pathogen, involving the activation of lymphocytes.

Contrast antigen and antibody.

An antigen is a substance that stimulates an immune response, while an antibody is a protein produced by plasma cells that identifies and neutralizes pathogens.

Describe the structure and function of antibodies.

Antibodies are Y-shaped proteins with binding sites for specific antigens, functioning to neutralize pathogens and mark them for destruction.

What are the functions of plasma cells and memory cells?

Plasma cells produce antibodies, while memory cells ensure long-term immunity by providing rapid responses to future exposures to the same antigen.

Explain the challenge and response mechanism of specific immunity.

The challenge and response mechanism involves the recognition of an antigen by T cells, followed by activation and proliferation of B cells to produce antibodies.

Describe activation of helper T lymphocytes by macrophages.

Macrophages present antigens to helper T lymphocytes, leading to their activation and subsequent stimulation of B cells.

Outline the structure and function of plasma B cells.

Plasma B cells are large cells that produce and secrete antibodies specific to the encountered antigen.

Describe clonal selection of plasma B cells.

Clonal selection involves the proliferation of specific B cells that recognize an antigen, resulting in the formation of plasma cells and memory cells.

Outline four modes of antibody action.

1. Neutralization of pathogens. 2. Opsonization for enhanced phagocytosis. 3. Activation of complement system. 4. Agglutination of pathogens.

Define immunity.

Immunity is the ability of the body to resist infection or disease.

What are two mechanisms of immunity?

Active immunity (producing antibodies after exposure) and passive immunity (transfer of antibodies).

Explain the differences between the primary and secondary immune responses.

The primary immune response is slower and weaker, while the secondary immune response is faster and stronger due to memory cells.

What are the consequences of HIV on the immune system?

HIV leads to a decrease in CD4 T cells, compromising the immune system and increasing susceptibility to infections.

Outline the relationship between HIV and AIDS.

HIV is the virus that causes AIDS, characterized by a severely weakened immune system.

List ways the HIV virus is spread.

HIV is spread through unprotected sexual contact, sharing needles, and from mother to child during childbirth or breastfeeding.

Explain the principle of vaccination.

Vaccination introduces antigens to stimulate the immune system to produce a response without causing the disease, thus providing immunity.

Describe the global initiative used to eradicate smallpox.

The global initiative involved widespread vaccination campaigns, surveillance, and containment of outbreaks, leading to the successful eradication of smallpox.

Define epidemiology.

Epidemiology is the study of how diseases affect the health and illness of populations.

Outline the role of an epidemiologist in vaccination programs.

Epidemiologists monitor disease outbreaks, evaluate vaccination effectiveness, and shape public health strategies to improve vaccination rates.

Describe how Jenner tested his smallpox vaccine.

Jenner tested his smallpox vaccine by inoculating a child with cowpox, exposing him to smallpox later to demonstrate immunity.

List reasons when Jenner’s test would not be approved today.

Reasons include lack of informed consent, ethical treatment of minors, and the need for extensive safety and efficacy data.

What is the source and function of histamine proteins?

Histamine is released by mast cells and basophils in response to allergens, functioning to promote inflammation and immune response.

List allergic symptoms caused by histamines.

Allergic symptoms may include sneezing, itching, swelling, and mucus production.

What is the function of an anti-histamine?

Anti-histamines block the action of histamines, reducing allergy symptoms.

Explain the production of hybridoma cells.

Hybridoma cells are produced by fusing a tumor cell with an antibody-producing plasma cell to create a cell that can proliferate and produce specific antibodies.

Define monoclonal antibody.

A monoclonal antibody is a laboratory-made molecule engineered to target specific antigens.

Describe the production of monoclonal antibodies in hybridoma cells.

Monoclonal antibodies are produced by cultivating hybridoma cells, which continuously secrete specific antibodies.

Outline the use of monoclonal antibodies in diagnosis and treatment.

Monoclonal antibodies are used for targeted therapies, diagnostics in laboratory tests, and research applications.

Describe how a pregnancy test strip works.

A pregnancy test strip contains immobilized monoclonal antibodies that bind to HCG; if HCG is present, it forms a visible line with free monoclonal antibodies.