Innate Immune System and Barriers to Infection

Question 1

What are the main roles of the immune system?

Answer 1

1) Defending the host (includes self from non-self and altered self)
2) Aid in the repair of injury

Question 2

What are the goals of the anatomical arrangement of lymphatic organs?

Answer 2

Protect key areas of the body where there is high risk or high likelihood of being infected

Question 3

What are the main organs of immunologic filtration?

Answer 3

Spleen—filters the blood
Liver—filters ingested material
Lungs–filters veins and air

Question 4

What is the only lymphatic organ without connection to the overall system?

Answer 4

Spleen—permits it to focus on cleaning the blood

Question 5

How is the risk of infection defined?

Answer 5

The dose of an agent and its virulence versus the resistance staged by the host

Question 6

How is the risk of infection depicted in terms of scientific fields?

Answer 6

Dose of bugs is an epidemiological function, virulence is microbiology, and resistance is a combination of anatomy and immunity

Question 7

What is the main prompt or urgent immunological response?

Answer 7

Infecting organisms multiply at a rate faster than the host and the high numbers of agents who can introduce infection at a given moment

Question 8

What are some of the reasons by which exposure to microbes does not lead to clinical infection?

Answer 8

1) exposure has a mutually beneficial result

2) host’s barriers reject the pathogen before its exposure leads to infection

Question 9

What are the three main stages of an infection?

Answer 9

1) exposure and establishment of infection
2) induction of an immune response and containment
3) down regulation and cure

Question 10

What is the generalized immune response that happens in the first four hours of infection?

Answer 10

Preformed, non-specific effector responses are engaged

Question 11

What is the generalized immune response that occurs up to about 4 days of infection?

Answer 11

Effector cells are recruited to an infection site that recognize that an infection has occurred. This leads to the activation of local effector cells and inflammation occurs

Question 12

What is the generalized adaptive immune response?

Answer 12

Antigens acquired in the earlier stages of immunity are presented to lymphoid cells, naive B and T cells are activated to antigens and clonal expansion and response occurs

Question 13

What is a general rule about the extent to which early and late immune responses function?

Answer 13

Early responses to infection are largely non-specific actions that provide barriers to immediate proliferation, later processes require heightened regulation but wage specific and permanent resolution to infection

Question 14

What are the goals of humoral immunity?

Answer 14

Counteraction of extracellular organisms by activating B cells to produce antibodies that eliminate extracellular components and enhance innate immune capacity

Question 15

What are the goals of cell-mediated immunity?

Answer 15

Activation of T cells to wage attacks against vacuolated or replicating intracellular pathogens to either lyse materials within vacuoles or to elimate infected cells

Question 16

What are some unique characteristics about adaptive immunity compared to innate immunity?

Answer 16

Adaptive immunity is molecularly specific with DNA recombination to permit explosive antigen recognition. It has memory capacity

Question 17

What are some of the barriers to an initial infection?

Answer 17

Epithelial and gastrointestinal flora, local chemical milieu, and some localized phagocytosis

Question 18

What are some of the innate mechanisms to infection?

Answer 18

wound healing, release of antimicrobial peptides, phagocytosis, and complement activation

Question 19

What stages occur if innate immunity fails?

Answer 19

APCs traverse to lymph nodes and present infectious antigens to T and B cells that launch an adaptive response to the invading organism

Question 20

What is the timeline of immune development in humans?

Answer 20

Early microbiotic exposures (neonate age) are essential to establishing adaptive cell populations. Range up to two years of age is essential for appropriate immune development. Complete system development occurs between 5 and 10 years of age; immune decay begins around 60 years of age.

Question 21

What are immunological concerns during the last trimester of pregnancy?

Answer 21

Despite the existence of a physical barrier, the mother must be made immunotolerant to the fetus and deals with suppression, meaning her risk for infection increases. The fetus must develop immunity late in gestation to prohibit adverse effects in utero, this raises risk of SA if infection occurs

Question 22

At what points are people most susceptible to infection?

Answer 22

Neonate periods due to introduction to pathogens with minimal immune functionality
Near one to two years with breast weaning
Late in life

Question 23

What are the main physical barriers that exist and what are their main mechanical means of blocking infection?

Answer 23

All four use epithelial cells with tight junctions.

1) Skin—Air flow
2) Gut–Fluid flow
3) Lungs/respiratory tract—Cilia
4) Naso/oropharynx–tears

Question 24

What are the main chemical means of blocking infection in the barriers?

Answer 24

1) Skin–fatty acids, beta-defensins, cathelicidin
2) Gut—low pH, pepsin, alpha defensins, cathelicidn
3) Lungs–surfactant, alpha defensins, cathelicidin
4) naso/oropharynx—lysozymes, histatins, and beta-defensins

Question 25

What is the immunological relevance of transferrin?

Answer 25

Sequestration of iron needed by bacteria for enzymatic and energetic functioning (cytochromes)

Question 26

What is the process of GI colonization from birth?

Answer 26

1) Sterility 2) Vaginal birth introduces lactobacillus (promotes lactose breakdown) 3) Maternal flora including bifidobacteria 4) aerobic species create reducing environment 5) anaerobes take over Which species arise is dependent on diet