Immunology Flashcards
Role of B cells
- neutralize bacterial toxins
- opsonisation of bacteria in extra cellular space
- activation of complement when bacteria in plasma
Role of stromal nurse cells
Provide nutrients and growth factors to nurture and direct the differentiation of developing blood cells
Role of CXCL12
Controls pre-pro B cell anchoring in correct stromal niche
Role of IL7
Required for lineage progression
Role of VCAM 1 and CAMs
Assist cell anchoring
Role of cKIT/SCF (stem cell factor)
Interaction induces intercellular signaling pathways to drive B cell development
Molecules expressed by mature B cells
- CD40
- MHC2
- BCR (IgM and IgD)
- B cell co-receptors (CD21,19,81)
Definition of a cytokine
Small soluble proteins secreted by one cell that can alter the behavior or properties of the cell itself or of another cell
Action of perforin on target cells
Aids in delivering contents of granules into the cytoplasm of target cell
Action of granzymes on target cells
Serene proteases activate apoptosis once in cytoplasm
Action of granulysin on target cells
Has antimicrobial actions and can induce apoptosis
Definition of active immunity
The production if antibodies as a result of exposure to antigen
Definition of passive immunity
Direct transfer of antibodies formed by another person or animal
Pregnancy-induced factors that may immune suppress the newborn
- tregs
- bregs
- HLA-G+ cells
- M2 macrophages
- myeloid derived suppressor cells
Characteristics of DiGeorge syndrome
- abnormal development of 3rd and 4th branchial arches
- immune dysfunction secondary to thymic hypoplasia or aplastic
Possible B lymphocyte defects
- X linked agammaglobulinaemia
- CD40 ligand deficiency
- IgA deficiency
- common variable immunodeficiency (CVID)
- transient hypogammaglobulinaemia of infancy
Differences in innate immunity in the newborn
- defective antigen presenting cell function
- phagocytic ability of cells is normal/increased, but less responsive to activation by cytokines
Difference in neonatal cellular immunity
- gamma delta T cells more prevalent
- effective production of IFN-g
What is different about neonate T cells
- produce less IFN-g
- lack constitutive perforin expression
Which way is infant immunity skewed?
Th2
Difference in neonatal humoral immunity
- Peyer’s patches and tonsils developed at birth but lack germinal centres for first weeks
- have delayed IgM production
- delayed ability to switch from IgM to IgG
Which antibodies transferred transplacentally?
IgG
Difference between T dependent and independent antigens
- dependent must contain a protein component so that T cell help can be received
- independent are multivalent
