vaccines

active immunity

occurs when body actively creates own B cell, T cell, and antibodies

produces own humoral and cell-mediated immune responses

passive immunity

occurs when body gets antibodies from foreign sources rather than producing antibody itself

natural immunity

occurs when body generates immune response naturally through normal life experience rather than medical means

artifical immunity

when a person intentionally introduces foreign substances to develop immunity

natural, active immunity

occurs when body produces antibodies responding to antigens

ex person gets sick due to microbe infection

natural, passive immunity

generally passed from mother to child during immune system development

IgG antibodies pass through placenta to fetus

IgA antibodies pass to children via breast milk

artificial, active immunity

vaccination involves injecting watered down pathogen versions

upon exposure, body develops immune response and prepares for full defense when exposed for real

vaccination typically conveys long term immunity

artificial passive immunity

antivenin treats animal venom poisoning, it serum containing antibodies from immune animals

antivenin injection and immune globulin therapy

attenuated vaccines

contain live but weakened microorganism strains that underwent attenuation, making them less virulent

injected then grow naturally and produce strong immune response

lifelong cellular and humoral immunity conveyance

trigger cell-mediated response

problems:

microbes may contain enough virulence to cause disease

modified viruses can occasionally mutate into virulent forms

measles, mumps, rubella

inactivated vaccines

dead microbes or fragments that cannot replicate or mutate to more virulent forms

often inactivated with formaldehyde

tend to be weaker, requiring high doses or multiple doses

need boosters

contain adjuvants= molecules making vaccines more effective by enhacing body immune response to antigens

problems:

killed pathogens have weaker antigens, only stimulate humoral response

vaccines often require boosters

flu

subunit vaccines

contain pathogen parts (antigenic fragments) stimulating immune response

1. toxoid vaccine= chemically or thermally modified toxins, more effective against bacteria diseases, ex. tetanus

2. virus-like particle (VLP) vaccines= contain intact viruses with no viral genetic material

3. recombinant vaccines= subunit vaccines created through genetic modification

polysaccharide vaccines

antigenic determinants from pathogen capsules

are not very immunogenic, so most be combined with more immunogenic proteins to form conjugated vaccines

recombinant vector vaccines

avirulent bacteria or virsues genetically modified to have genes coding for antigens

nucleic acid vaccines

air pressure, gene guns, or nanoparticles to deliver mRNA or DNA to host cells

host cells express these genes and host immune systems respond to foreign proteins, stimulating humoral and cellular immunity

first COVID-19 vaccines

reverse vaccinology

uses bioinformatics to develop vaccines more quickly and efficiently than standard methods

genome sequencing

predict best epitopes

hypersensitivity

any exaggerated immune response

immunopathology= study of hypersensitivity reactions

four major types of hypersensitivity

type 1 (immediate type) hypersensitivity

involves cells with IgE antibody receptors, including mast cells and basophils

IgE antibody exposure triggers degranulation and inflammatory chemical secretion, producing inflammatory response

involve:

histamine= increases capillary permeability

prostaglandins= increase mucus secretion and affect smooth muscle

leukotrienes= cause prolonged smooth muscle contraction

localized reactions: caused by ingesting or inhaling antigens, producing common reactions like hay fever, hives, and asthma

system anaphylaxis= anaphylactic shock is type one that spread throughout the whole body, producing potentially fatal shock and breathing difficulties

for allergies goal is to have IgE lower and increase IgG

antihistamines= block histamine receptors on target cells

cromolyn sodium= block calcium influx into mast cells

epinephrine= stimulates cAMP production

cortisone= reeduces histamine levels and stimulates cAMP production by mast cells

type 2 (antibody-mediated) hypersensitivity

involves IgG antibody to mediate cell destruction with complement system help

cell-surface antigens activates complement system and causes target cell destruction, which can be maladaptive

mediated by IgG antibody and the complement system

ex. blood transfusion reactions= need to make sure right antigens are given

erythroblastosis fetalis= hemolytic disease of the newborn, condition involves mother’s IgG molecules passing through placenta to fetus and attacking fetal red blood cell, can have Rh factor or do not, Rh- mothers may develop Rh+ babies, second pregnancy has more of a response, prevent allergic reaction with Rhogam

type 3 (immune-complex mediated) hypersensitivity

inflammatory response produced by immune complex deposition throughout the body

these lodge in basement membranes under cells and activate complement system and trigger inflammatory response mediated by large numbers of neutrophils

localized or systemic:

lupus= kidney glomeruli, causing inflammation and tissue damage

Rheumatoid arthritis= joint tissues, causing inflammation and pain

serum sickness= body produces antibodies against those foreign proteins, causing sickness

type four (delayed-type) hypersensitivty

cell-mediated sensitivity not showing up immediately

ex tuberculosis and transplant

tissue rejection

allograft= transplant between genetically different individuals of the same species

isograft= transplant between identical twins

autograft= transplant using one’s own tissue

xenograft= transplant between donor and recipient of different species, often problematic due to high hyperacute rejection chance as human immune systems try to overcome nonhuman antigens

recipients body attacks transplanted tissue, t helper cells assist cytotixc t cells in destorying tissue and may release cytokines to stimulate tissue destruction via macrophages

need to match MHC molecules

privileges sites= cornea and heart valves, places least liekly to be rejected