Lecture 34 Flashcards
Where do IgM and IgD producing cells come from
Primary focus
Which immunoglobulins to memory B cells express
Mainly–>IgG (some IgA and IgE) and further undergoing somatic hypermutation
Some–> IgM
What does Memory B cells express higher levels of than naive B cells
Higher levels of
1) MHC class II
2) CD40
3) Receptors for survival and proliferation
Where do Memory B cells reside
Circulate in blood
Reside in spleen and lymph nodes
Types of Memory T cells
Central memory T cells (Tcm) and Effector memory T cells (Tem)
Where do Central memory T cells (Tcm) reside/travel
Between secondary lymphoid tissues
Effect on Central memory T cell after second antigen exposure
Rapidly reactivate
Which memory T cell can differentiate into several subtypes
Central memory T cell (Tcm), depending on cytokine environment
ex. (Th1, Th1…)
Where do Effector memory T cells (Tem) travel
To/Between Tertiary tissues
Which Memory T cell contributes better to first-line defense
Effector memory T cells (Tem) as they can interact with local APC
Effect on Effector Memory T cell (Tem) after second antigen exposure
Shift right back into effector functions
Do Memory T cell require strong co-stimulatory signal or cytokines
NO, already have large expression of CD28
What differentiated Tcm and Tem
Location and commitment to effector function
Which T cells are memory T cells closer to
Closer to effector T cells than naive T cells
Memory T cell vs effector T cell
Memory T cell
1) Requires less for activation
2) Express unique set of receptors (different surface adhesion molecules and costimulatory receptors)
3) Less sensitive to restimulation, but still require contact with p:MHC
Become effector upon reactivation
Memory T cells Fate determinants
1) Cytokines (IL-7, IL-15)
2) Notch1
3) Strength of antigen interaction
Action of IL-7
IL-7 increases expression of Bcl-2 (an anti-apoptotic factor)
Which memory CD cells are more abundant
CD8+ T cells, but still require help of CD4+ T cell for longevity
What is it to Immunize
Make someone or an animal resistant to a particular infectious disease or pathogen
How can protective immunity be achieved
By passive or active immunization
What is Passive immunity
Temporary adaptive immunity through the transfer of immune products (no memory)
ex. Antibody (serum) from an immune individual to an nonimmune one
Examples of Passive immunity
Monoclonal therapy for SARS-CoV-2
Breastmilk from mom to newborn
ZMapp therapy against Ebola virus (combination of 3 monoclonal antibodies)
What is active immunity
Adaptive immunity induced by natural exposure to a pathogen or by vaccination
When to use Passive immunization
1) Immune deficiency
2) Toxin or venom exposure with immediate threat to life
3) Exposure to pathogens that can cause death faster than an effective immune response can develop
What is Original antigenic sin
When memory cells are enlisted rather than activating naive cells (once we have an effective response)
Can happen in both passive and active immunization
What can Active immunization induce
Immunity and memory
How can active immunization be acquired
1) Natural exposure to infectious agent (chickenpox parties)
2) acquired artificially (vaccination)
Mechanism of Vaccination
Purposefully inducing specific immune response (with memory) by exposing a person to an altered and non-dangerous form or component of the infectious agent
What lymphocytes does Active immunization recruit
B and T cell response
Function of Adjuvants
Enhance immune response to a vaccine
Found in attenuated vaccines
What is an attenuated vaccine
A vaccine containing a virus with multiple mutations to prevent productive infection in immunocompetent humans
Have built-in adjuvant
What is Herd immunity
When the majority of the population is immune to an infectious agent, significantly reducing pathogen reservoir (due to low chance of susceptible individual contacting infected individual)
