immunology pt. 2 Flashcards
endotoxins
cell-associated substance
- less toxic, potent, and specific than exotoxins which could end in shock w/ antimicrobial therapy
- Lipid A of LPS in the cell envelope of certain G- bacteria, is a toxin when solubilized
> bacterial cell death + division
- lipoteichoic acid in the cell envelope of certain G+ bacteria
Portal of Exit
pathogen exits the body to infect new individual
- may contribute to signs of disease
factors affecting pathogenesis development of disease
- host risk factors for infections
- general health
- genetics
- previous exposure
- injury/medical intervention
- patient compliance - microbe
- virulence factors
- antimicrobial resistance
- infectious dose - environment
- PoE
- nutrients
- O2, pH, and temp
- medical personnel compliance
bacterial infectious process (growth)
pathogenicity
- pathogen can inflict damage on host
virulence
- relative ability of pathogen to cause disease
- many pathogen use a combination of toxins, invasiveness and other virulence factors
immunology
study of host defense rxns to foreign substances/non-self introduced to the body
immunity
state of protection (by individual) from infectious agent/substance
- active ability to resist the disease
composition
complex sys of organs, tissues, cells, and cell products that help the body distinguish self from non-self
- cells separated throughout the body = mainly leukocytes (WBC)
- mobility
> sys can be conc at the site of infection
> will disperse w/ resoln
- communication between sys components ensures a coordinated total immune response
immune sys func
protect the host from pathogens + malignant cells
- 2 step process
immune sys recognition
based on chem. differences between self + non-self molecules
- harmful vs. innocuous non-self
- sterile vs. non-sterile sites
- differences between individuals of same species
> Rejection of organ transplants
immune sys response
foreign agent destroyed/neutralized
- effector response, cells, and molecules
immune sys failure
hypersensitivity
- immunopathology due to an overactive immune response
- allergy: to innocuous substance
- autoimmune disease: to self
immunodeficiency: immune sys component absent or functionally defective
malignancy
lymphatic sys + organs (primary)
lymph
lymphatic
organs
- primary (generative); site for generation + maturation of lymphocytes
> bone marrow
= hematopoiesis: generation of all immune sys cells
= B cells mature in bone marrow
>thymus
= T cells mature in thymus
lymphatic sys + organs (secondary)
secondary (peripheral): site for antigen-lymphocyte interactions; immune sys cells passing the encounter antigens bound to Pro-APCs conc in organs
- lymph nodes: localized/regional filtering station for lymph
> origination of adaptative immune responses to localized pathogens
- spleen: filtering station for blood
> origination of adaptative immune responses to systematic pathogens
- MALT: mucous associated lymphoid tissue
>peyer’s patches, tonsils, adenoids, appendix
cells of immune response
lymphocytes: mediate adaptive immune response
- antibodies made by B cells, like actions of neutrophils + macrophages are effective at dealing w/ pathogen before they can infect the cell
- cytotoxic T cells + natural killer cells (NKC)
> effective at dealing w/ cells after they have become infected by pathogens
immune sys molecules
cytokines: small soluble cell signaling proteins
- hormones-like factors coordinate efforts of immune sys
- chemokines (chemotactic vs. chemotaxis)
> chem attractants, direct chemotaxis
- lymphokines
> made by lymphocytes, activator in signal transduction path altering transcription, and chem. attractants
- interleukins
> promote differentiation of lymphocytes + hemopoietic cells
- complement: important series of proteins in innate + adaptive response
non specific response
innate
non-antigen specific
response = antigen independent
immediate max response
exposure result in no immunological memory
specific response
adaptive
antigen specific
response = antigen dependent
lag time between exposure + max response
exposure results in immunological memory
innate immunity func
protection against
1. NF invasion
2. pathogen colonization, infection + disease
innate immunity outcome
- most microbes destroyed before infection established
- «_space;pathogen replication
what is non-self?
- pathogen associated molecular pattern (PAMPS)
- surface macromolecules w/ repeating pattern on infectious agents
- internal agents - danger associated molecular pattern (DAMPs)
- cell distress signals (tissue damage)
- may result in noninfectious inflammatory response
how is non-self recognized?
- pattern recognition receptors (PRRs)
- membrane-bound: receptor on phagocytic cell membranes/endosomes; bind infectious agents
ex. Toll like, complement, and FC receptors - cytoplasmis: receptor in cells that bind infectious agents
- soluble: secreted
ex. MBL (mannose binding lectin), CRP (C-reactive protein)
innate resistance
hosts have innate resistance to most pathogens
1st line of defense: physical/chem barriers and biological
innate (non-specific) resistance
2nd line of defense
1. humoral + cellular barriers to infection
- cells capable of killing foreign + altered self target cells in non-specific manner
2. inflammation + inflammatory response
humoral barriers to infection
- iron binding proteins
- lysozyme
- antimicrobial peptides
ex. defensins - coagulation
- cytokines
- interferons - complement
