WEEK 3 - Host-Microbe Interactions 2

What coordinated group of proteins is activated by the immune system or in response to invading microorganisms?

Complement system

What process involves a cascade of biochemical events that attract and enhance the activity of phagocytes?

Chemotaxis

Which complement system product attracts neutrophils and macrophages to the site of infection?

C5a

What is produced by C5 convertase that acts as a chemoattractant for immune cells?

C5a

Which nonspecific immune response includes increased blood flow and the attraction of immune cells to infection sites?

Inflammation

What system, composed of a wide variety of proteins, attracts phagocytes and increases blood and fluid flow to infection sites?

Coagulation system

What is one function of the coagulation system in inflammation?

Attracts phagocytes to the site of infection

What is another function of the coagulation system in inflammation, related to blood and fluid?

Increases blood and fluid flow to the site of infection

How does the coagulation system inhibit the spread of microorganisms?

By physically walling off the site of infection

What are proteins secreted by macrophages and other cells that enhance various immune activities?

Cytokines

What immune system molecules have multiple effects essential to nonspecific and specific defensive responses?

Cytokines

What proteins are also known as immunoglobulins and are key components of the specific immune response?

Antibodies

Which class of antibody is the first produced during an immune response?

IgM

Which antibody class is the most abundant in the body?

IgG

Which class of antibody is secreted in body fluids like tears?

IgA

Which class of antibody is involved in responses to parasitic infections?

IgE

Which antibody class is responsible for regulation of antibody production?

IgD

What tool is used in laboratory diagnosis of infections based on measuring specific antibody production?

Ability to measure specific antibody production

Which branch of the immune system is also known as humoral immunity?

Antibody-mediated immunity

Which branch of the immune system is also called cellular immunity?

Cell-mediated immunity

Which type of lymphocyte is primarily responsible for producing antibodies?

B Lymphocytes (B Cells)

Where are B lymphocytes primarily located?

Lymphoid tissues (lymph nodes, spleen, GALT, tonsils)

Which B cell subtype is inactive and waiting for antigen stimulation?

B lymphocytes

Which B cell subtype is activated and secretes antibodies in response to an antigen?

Plasma cell

Which B cell subtype is long-lived and preprogrammed for future antigen exposure?

B-memory cells

Which type of lymphocyte circulates and resides in lymphoid tissues and has multiple immune functions?

T Lymphocytes (T Cells)

Where are T lymphocytes primarily found?

Lymphoid tissues (lymph nodes, spleen, GALT, tonsils)

Which T cell subtype interacts with B cells to facilitate antibody production?

Helper T cells (TH)

Which T cell subtype recognizes and destroys host cells invaded by microorganisms?

Cytotoxic T cells (TC)

Which T cell subtype mediates regulatory responses within the immune system?

Suppressor T cells (TS)

Which immune cells function like cytotoxic T cells but do not require antigen presence for activation?

Natural Killer Cells (NK Cells)

Which cells are preprogrammed to produce specific antibodies immediately upon re-exposure to an antigen?

B memory cells

What process involves antibodies coating microorganisms to enhance ingestion by phagocytes?

Opsonization

Which immune function of antibodies neutralizes harmful microbial toxins?

Neutralization of microbial toxins

What antibody action promotes clumping of bacteria to aid in clearing infection?

Agglutination

Which antibody function inhibits movement of bacteria?

Inhibition of bacterial motility

Which antibody action blocks viruses from entering host cells?

Viral neutralization

Which immune response is activated when antibodies combine with microorganisms?

Complement and inflammatory response activation

What is the term for the multiplication of B cells that specifically recognize the antigen that stimulated activation?

Clonal expansion

Which type of immune cell processes and presents antigens on its surface to attract helper T cells?

B cell

What cells stimulate B cells to mature into plasma cells?

Activated helper T cells

What type of cell is responsible for increased production of highly specific antibody?

Plasma cells

What antibody class is typically produced first during an immune response?

IgM

What antibody class is produced after class switching for stronger immune response?

IgG

Which type of immune cell retains antigen memory for faster future responses?

B-memory cells

What receptors on B cells recognize microbial antigens?

Antigen receptors

Which immune cells assist B cells in antibody production?

Helper T cells

Which immune cells target and destroy host cells infected with microorganisms?

Cytotoxic T cells

What are examples of antigen-presenting cells (APCs)?

Macrophages, dendritic cells, B lymphocytes

What activates T lymphocytes?

Antigen recognition via antigen-presenting cells

What do activated helper T cells release to stimulate other immune cells?

Cytokines

What do cytokines stimulate?

Phagocytes, NK cells, and components of inflammation

What happens to cytotoxic T cells upon activation?

They increase in number and destroy infected host cells

What is the term for the growth and multiplication of microorganisms that cause damage to the host?

Infection

What results when infection causes notable physiological changes or organ system dysfunction?

Disease

What are microorganisms that cause infection or disease?

Pathogens

What refers to characteristics that enable pathogens to cause disease?

Virulence factors

What is the ability of an organism to cause disease?

Pathogenicity

What measures the degree of pathogenicity of an organism?

Virulence

What microbial factors contribute to colonization by allowing attachment and invasion of host surfaces?

Attachment and invasion

What microbial adaptation allows localization in moist areas or protection in inhaled/ingested debris?

Survival against environmental conditions

What structures enable bacteria to adhere to host cell surfaces?

Pili

What surface structures or molecules allow microbes to attach to host cells?

Adherence proteins

What structured microbial communities enhance colonization and resist clearance?

Biofilms

What molecules help bacteria compete with the host for nutrients like iron?

Siderophores

What microbial feature enhances movement toward host surfaces?

Motility

What host skin disruptions allow microbial invasion?

Trauma, abrasions, burns, surgical wounds, needle sticks

What condition results from inhalation of toxic substances that predispose to infection?

Inhalation damage (e.g., smoking, gases, particulates)

What artificial medical item can allow microbial implantation?

Medical devices

What medical conditions predispose the host to microbial infection?

Malignancies, diabetes, alcoholism, other diseases

What can alter normal flora and promote infection through microbial imbalance?

Overuse of antibiotics

What microbial structure helps avoid killing by phagocytes by preventing ingestion?

Capsule

What microbial strategy inhibits phagosome-lysosome fusion inside phagocytes?

Avoiding phagocyte-mediated killing

What microbial action allows them to survive inside phagocytes by resisting lysosomal enzymes?

Resistance to destructive lysosomal agents

What is the microbial strategy that enables rapid replication inside phagocytes?

Intracellular multiplication

What microbial products directly damage or kill phagocytes?

Toxins and enzymes

What microbial strategy hides surface molecules from complement activation?

Capsule and biofilm formation

What substances are produced to prevent complement activation or destroy complement proteins?

Complement-inhibiting or complement-destroying substances

What microbial strategy involves overwhelming the host before the immune system can respond?

Rapid invasion and multiplication

What process involves destroying cells that are part of the immune defense?

Invasion and destruction of immune cells

What microbial strategy involves hiding inside host cells to avoid detection?

Survival in host cells and immune evasion

What structure can microbes use to mask antigens and prevent immune activation?

Capsule or biofilm

What strategy involves changing surface proteins to neutralize immune memory?

Antigenic variation

What microbial product destroys or inactivates antibodies directly?

Proteases

What term describes biochemically active substances released by microbes that affect host cells?

Toxins

What type of illness results from ingestion of preformed microbial toxin, such as in botulism?

Intoxication

What general type of toxin is found in almost all gram-negative bacteria?

Endotoxin

What is the component of endotoxins in gram-negative bacteria?

Lipopolysaccharide portion of the cell envelope

When are endotoxins released by bacteria?

When the gram-negative cell is destroyed

What are some effects of endotoxins on the host?

DIC, fever, complement activation, shock, death

What type of toxin is commonly produced by gram-positive bacteria?

Exotoxin

Do exotoxins require bacterial death to be released?

No, exotoxins are secreted by living bacteria

What kind of host targets do exotoxins typically affect?

Specific host cells

What do some exotoxins do to aid bacterial spread in tissues?

Kill host cells or degrade tissue components

What do some exotoxins interfere with inside host cells?

Intracellular functions like protein synthesis, signaling, or neuromuscular transmission