M: Adaptive immunity 1 - Week 4 Flashcards
List 3 innate defences to infection found at the ocular surface of they eye
- Lids, tears: wash away microbes, inhibit growth
- Complement: lyses bacteria and enveloped viruses; attracts phagocytes
- Tissue macrophages + Neutrophils: phagocytose microbial survivors
Where on the ocular surfaces is complement found?
in tears and conjunctival tissue
What happens to the level of tissue macrophages and neutrophils when lids are closed?
Increases
List 3 innate defences to infection found at the anterior chamber of the eye
- Structure itself: prevents microbe access
- Complement: lyses bacteria and enveloped viruses
- innate immune system: activated by PAMPs
How much does the anterior chamber of the eye rely on physical and soluble mediators to prevent infection? Why is this the case?
Heavy reliance on physical and soluble mediators because a cellular response would impair vision
How can organisms overcome the innate defences of the eye? (3)
- they gain access to anterior chamber via trauma or blood
- they have specific adhesins for the ocular surface
- they can overcome the innate immune system
In regards to lymphocytes:
A) What immune system are they involved in?
B) Name the 2 types of lymphocytes
C) What are lymphocytes derived from?
D) What do lymphocytes recognise?
E) Where are the 2 types of lymphocytes derived?
A: Adaptive B: B and T lymphocytes C: Haemopoietic stem cells D: Antigen E: B lymophocytes = bursa. T-lymphocytes = thymus derived
How do the 2 types of lymphocytes bind antigen?
B-lymphocytes: Binds whole antigen
T-lymphocytes: Receptor binds antigen peptide displayed on Antigen Presenting Cells
How many different antigens can a lymphocyte recognise?
A lymphocyte has multiple copies of a unique receptor only, which means that a single lymphocyte can only recognise a single unique antigen.
However, it has multiple receptors for this antigen and can bind to multiple of this particular antigen
How and where are T and B cell receptors generated?
By random somatic gene rearrangements during differentiation in the primary lymphoid tissues (Bone marrow/Bursa for B cells and Thymus for T cells)
When can T ad B cells leave the primary lymphoid tissues after differentiation?
When these cells express receptors for non-self antigens
If they express receptors for self antigens, they are destroyed
Where in the primary lymphoid organs do lymphocytes develop? (3)
- foetal liver
- bone marrow
- thymus
What happens once a lymphocyte is released from the primary lymphoid organ?
Is released as a “Naive lymphocyte” as it hasn’t encountered antigen. It travels to our bloodstream and then either enters the spleen or back into the lymph node, an then travels back to the bloodstream.
It does this until they’ve encountered antigen (in the lymph node or spleen).
Once encountered antigen, the “Activated lymphocytes” travel back to the bloodstream and then start entering the tissues and then circulate between the tissues and bloodstream
Where do naive lymphocytes first interact with foreign antigens? (3)
In the secondary lymphoid organs:
- spleen
- lymph nodes
- molecular associated lymphoid tissues (MALT)
List the 7 lymphoid tissues of the adaptive immune system in the body
- conjunctival associated lymphoid tissue
- adenoid
- tonsil
- lymph node
- spleen
- appendix
- large intestine
Where can you find the 3 eye-associated lymphoid tissues?
- lacrimal gland
- lacrimal drainage system
- conjunctiva
How are lymphocytes spread in the conjunctiva?
Diffusely spread among the cells of the conjunctiva. Found in “follicles”
What name do we often use to refer to the tissues and structures associated with our mucosal tissue?
Common Mucosal Immune System
True/False: There are lymph vessels that drain from the conjunctiva
True
True/False: There aren’t any lymph nodes that drain from the eye and anterior chamber
True
Where do a lot of the antigens present in the ocular departments drain to? What does this mean?
Drain to the spleen. Therefor a lot of immune responses are actually induced in the spleen
Describe the vascularity of the central cornea. Where in the cornea are dendritic cells present?
The central cornea is avascular. Dendritic cells are present only in the peripheral corneal epithelium
Is there any lymphatic drainage in the cornea? Explain
No lymphatic drainage. Most of the dendritic cell antigens from the cornea are drained through the blood and delivered to the spleen
Why are immune responses in the intraocular compartment of the cornea often suppressed?
Because otherwise the immune activation would damage/impair our vision
