Adaptive immune responses against viruses Flashcards
Difference between intrinsic and innate immunity vs acquired immunity
Acquired immunity is tailored to pathogens already encountered in the past
It has immunological memory
Where is adaptive immunity exploited in humans?
Dysregulation of adaptive responses can lead to ____, ___ and ___
Immunization
Immune deficiency, autoimmunity and immune hypersentivity
Name the important primary and secondary lymphoid tissues
- Primary lymphoid tissues produce and mature lymphocytes
examples, thymus and bone marrow
- Secondary lymphoid tissues provide space to immune cells to interact with virus particles
eg. Lymph Nodes
Spleen
SALT
NALT
BALT
GALT
About T cells:
T cells are produced in the ____ and then migrate to the _____
what do these T cell express ____ and what kind of selection do they undergo and why?
Two major subtypes of T cell
What do t cell release to kill virus infected cells
- bone marrow, thymus
- TCR (T-cell receptor), positive and negative selection. In positive selection, it is checked whether or not the t cell are able to recognise their self-cells while in negative selection, it is seen whether the t-cells are killing their self-cells or not. If they are, they are removed.
- CD4+ and CD8+
- Perforin and Granzymes
What are the functions of CDT4+ helper cells?
- Activate B memory cells
- Activate cytotoxic T cells
- Induce antiviral state by releasing cytokines and IFNs
- Activate APCs
About natural killer t cells
- are different from _____
- recognize ____ antigens presented by _____
- after activation, they release _______ which in turn activate ___, ___, ___ and -__
Viruses such as __, __, __, have evolved mechanisms to evade NKT response
- Natural killer cells
- lipid, CD1d
- IL-4 and IFNy as well as IL-1, IL-2, IL-3, IL-7 and IL-21 as well as TNF-alpha
- HIV, HSV-1, cytomegalovirus, poxviruses)
About B-cells:
- B cellsare producedin the___ and become activated in ____ and ____
- There is a rearrangement of gene segments called ___, ___ and ___ that leads to the formation of several combinations of __ and ___
- ABs produced can be inserted or secreted to produce ___ or ___.
- what is positive and negative selection of B cells?
- When naïve B cells become activated by an antigen, they undergo proliferation and exhibit a phenomemon called ____
- they also differentiate into ___ and ___
- B cells also ___ and ____
- Bone Marrow, in spleen and lymph nodes
- V (variable), D (diversity) and J (joining) - immunoglobins light and heavy chains
- B-cell receptors and free ABs
- To check if B cells are able to recognize self-cells without killing them
- immunoglobin class switching - Memory B cells and Plasma B cells
- present antigens and produce cytokines
About ABs
- Two ways in which ABs function
- regions of AB that bind antigens and regions of AB that bind immune cells
- igG
- igM
- igA
- igD and E
- they neutralize viruses or they flag virus infected cells for elimination
- Fab and Fc
- main AB
- produced by igG during viral infections
- produced in mucosa secretions and prevents transmission
- activate mast cells and basophils and are important for extracellular pathogens
___ and ___ cells protect from reinfections
—– can survive decade while ___ have a shorter life span
With age, they undergo _____ and become less responsive to infection
name three processes that are associated with loss of functional memory cells reactive latent infection or they worsen chronic infections
- Memory B and T cells
- Memory B cells, Memory T cells
- immunosenesence
- Aging, chemotherapy and immunodeficiency
- The aim of neutralizing ABs
- they most commonly target the ____ of enveloped virus (eg, __ and __) and the capsid of non-enveloped viruses
- the virus-ab complex is targeted by ____
-____ and _____ allow viruses to evade antibody responses - Viruses bury their functional epitopes in ___ or use ____ to escape ab binding
- the neutralizing ABs bind to viruses and prevent them from entering the cells
- glycoprotein, HIV and sar-cov2,
- macrophages
- antigenic drift and antibody escape mutations
- complex protein structures and glycan shields
what do non-neutralizing ABs do? What kind of cells recognize these ABs, give examples?
Name of phenomenon
What kind of viruses escape this? give phenomenon.
Two consequences of ADCC-
- they bind to ABs in such a manner that they are recognized by immune cells (flag). that have FC-receptors and recognize Fc-regions of cells. Macrophages, NKCs, B cells and lymphocytes.
- Antibody dependent cellular toxicity (ADCC)
- macrophage trophic viruses, HIV-1 and dengue viruses
- ADE and makes the symptoms or pathology worse
Complement pathway:
- antibody binding can lead to activation of ____ which lyses viruses
- two complement pathways: can be activated by viral particles of ___, __ and ____
- two ways in which they kill
- what ways have viruses evolved to use the complement pathway to their advantage
- classical complement pathway
- alternate complement pathway and mannose-binding lectin (MBL) pathway. HIV-1, sar-cov2 and EBOLA
- they either directly lyse the bacteria or they surround the virus with complement particles to mark it for destruction
- they use complement particles to enter the immune cells called langherans cells to increase the transmisson of HIV-1
- What does igA at mucosal surfaces do?
- It uses its ___ region to active other immune cells
- binding of igA to viral components leads to _____ which is the ____
- they are composed of ____ which binds and ____ pathogens
- however, they worsen ___ and ___
- It neutralizes viruses before they enter the body
- Fc
- NETosis, formaton of neutrophil extracellular traps
- neutrophil DNA , traps
- symptoms and pathology
