Immunology Flashcards

1
Q

Describe the sterility of the uterus

A

Sterile except when cervix opens in oestrus

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2
Q

Outline the immunological challenges of the female reproductive tract

A
  • Commensal flora
  • Infectious agents
  • Sperm
  • Semi-allogenic foetus
  • Seminal plasma
  • Oestrogen
  • Progesterone
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3
Q

What does semi-allogenic mean?

A

From the same species but sharing half the genetic material

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4
Q

Describe seminal plasma as a challenge to the female reproductive tract

A
  • Induces local inflammatory changes
  • To protect agains infectious agents introduced during intercourse
  • Inflammatory response when semen comes into contact with vagina, cervix and uterus
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5
Q

Describe oestrogen on terms of female reproductive tract immunology

A
  • Influx of leukcocytes at oestrus
  • Pro-inflammatory factors prior to implantation in association with pre-implantation surge of E2
  • Insemination: infectious material cleared rapidly
  • Th1 dominant (CD4 Th, IFNy and CMI)
  • Pro-inflammatory
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6
Q

Describe progesterone in terms of female reproductive tract immunology

A
  • Anti-inflammatory
  • INduction of immunoregulatory protein
  • When binds to immune cells, produce factors that are immuno-suppressive
  • Th2 dominant (CD4 Th producing IL-4, -5, -9, -13)
  • Pregnancy has bias towards Th2 (anti-inflam) immunity
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7
Q

Explain the concept of the foeto-placental allograft

A
  • Foetus and trophoblasts expressing antigens (MHC I) from father, but not rejected by mother
  • The conceptus can be considered as 2 grafts - foetus and trophoblast
  • Trophoblast is the first barrier to maternal immunity
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8
Q

List mechanisms by which the foetus may avoid maternal immuno-rejection

A
  • Trophoblast as first barrier to maternal immune response
  • Decidua and endometrium
  • Greater number of layers between maternal and foetal blood (more layers = less challenge to immune system)
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9
Q

Describe the formation and function of the decidua and endometrium in relation to foetal avoidance of maternal immuno-rejection

A
  • Formed in response to progesterone
  • Prepares uterus for embryo
  • Secretory phase
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10
Q

Describe the development of the decidua in primates and rodents prior to pregnancy

A
  • Increases glandular epithelial secretions (oedema) at secretory cells
  • Promotes formation of spiral arterioles
  • Shed when progesterone declines
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11
Q

Describe the development of the endometrium in farm animals prior to pregnancy

A
  • Increase in glandular secretions
  • Increase in blood vessels and blood flow
  • Re-absorbed when progesterone declines
  • No menstruation
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12
Q

Explain why the trophoblast is antigenically unusual

A
  • Does not express some of paternal antigens easily recognised by maternal immune system
  • E.g. MHC class I
  • Makes placenta resistant to recognition and attach by maternal immune cells
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13
Q

What does the type of immune cells present in uterus depend on?

A
  • Differs between species
  • Presence of decidua or endometrium
  • Degree of trophoblast invasion
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14
Q

Describe the immune cells in species with decidua

A
  • Human and non-human primates
  • NK cells 75% of decidual leuckocytes
  • Interact with placental antigens
  • Normally result in production of local factors supportive of pregnancy e.g. immunosuppressive
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15
Q

Describe the immune cells in species with endometrium

A
  • Includes domestic animals
  • No uterine NK (except pigs)
  • Macrophages
  • Specialised T cells (sheep, horse)
  • Immunosuppression, growth enhancement, placental detachment at parturition
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16
Q

Describe the immunological features of binucleate cells in ruminants

A
  • Uni-nucleate trophoblast cells have very little, if any MHC-I
  • Increased expression as BNCs migrate
  • Foreign antigens deliberately upregulated
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17
Q

Explain the immunological implications of the binucleate cells in ruminants

A
  • Migrate and fuse with maternal cells
  • Upregulation of MHC-I
  • Exposure and prime maternal immune system so that system recognises pregnancy and responds in beneficial way
18
Q

Compare the antigens expressed on chorionic girdle cells vs endometrial cups

A
  • Cells: MHC-I positive

- Cups: MHC-I negative

19
Q

Explain the immunology of the formation of the endometrial cups, and its role in maternal recognition of pregnancy

A
  • Chorionic girdle cells are MHC-I postive
  • Trophoblast cells are MHC-I negative
  • Endometrium is MHC-I positive
  • When the girdle cells invade, switch from MHC-I positive to negative as become endometrial cup cells
  • Following invasion, only the endometrial cells are MHC-I positive
  • Invasion sends signal to mother that she is pregnant and needs to adapt her immune response
20
Q

Describe the maternal immune response to the invasion of the endometrial cup cells

A
  • Accumulation of maternal leukocytes around base of cups
  • Mononuclear cells invade between cup cells
  • Immunce cells detroy cup cells (do not know hwat the target of these is)
  • Pregnancy induces local cell mediated immune response
21
Q

What type of leukocytes accumulate around the endometrial cups?

A
  • Mainly T cells

- Some B cells

22
Q

What antibodies are prodced by most maiden mares in their first pregnancy in response to the girdle cell invasion?

A

Cytotoxic antibodies to the antigens expressed on girdle cells

23
Q

During pregnancy and locally in the pregnant uterus, what is the conceptus protected by in the mare?

A
  • Modified and protective maternal immune response
  • Factors secreted by trophoblast dampen damaging immune response
  • Factors secreted by pregnant endometium that also dampen any damaging immune response
24
Q

What are the immunological implications of the cups?

A
  • Modulation of local vs systmic immune responses
  • Split tolerance between systemic and local immune respnse
  • Important as mare needs to be able to respond to pathogens, but not damage foetus
25
Q

What is meant by split tolerance in the mare?

A
  • Systmic responses normal

- Uterine responses dampened

26
Q

What are the 2 immune responses to pregnancy seen in the mare?

A
  • Cytotoxic antibodies commonly released by maiden mares

- T lymphocytes (and some B) accumulation around the base of the endometrial cups

27
Q

What are defensins?

A

Small, cysteine rich cationic proteins that act as host defence peptides

28
Q

What are the actions of defensins?

A
  • Active against bacteria, fungi and many enveloped and non-enveloped viruses
  • Most defensins function by binding to microbial cell membranes
  • Once embedded form pore, allows efflux of essential ions and nutrients
29
Q

What are immunoglobulins?

A

GLycoprotein molecules produced by plasma cells, aka antibodies

30
Q

What immunoglobulins are secreted by the reproductive tract?

A

IgG, IgA and IgM

- IgA and IgG most important

31
Q

Compare immunoglobulin transfer in invasive and non-invasive placentas

A
  • Invasive have transver of IGG in utero

- Non-invasive only have milk transfer

32
Q

What immune cells are present in the placenta?

A
  • NK cells in decidua only (except pig)
  • Macrophages and specialised T cells in non-deciduate
  • Lymphocytes important in both (Th2 cells in particular)
33
Q

Give the cell type, receptor and antigens involved in inflammation causing abortion

A
  • Host receptors involved: CD4+ Th1 cell receptors
  • Recognise paternal MHC class II antigens
  • TLR s are main receptors
  • Recognise PAMPs
34
Q

Give Gram type, morphology and biochemical test results for E coli

A
  • Gram -ve
  • Rod shaped, flagellated
  • Lactose fermenter (pink on MacConkey)
35
Q

Give the Gram type, morphology and biochemical test results for Staphylococcus aureus

A
  • Gram +ve
  • Round
  • Catalase positive
36
Q

Give the Gram type, morphology and biochemical test results for Pasteurellla

A
  • Gram -ve
  • Pleomorphic
  • Catalase and oxidase positive, facultative anaerobe
37
Q

Give the Gram type and morphology for Haemophilus

A
  • Gram -ve

- Pleomorphic

38
Q

Give the Gram type, morphology, biochemical tests and pathogenicity of Proteus

A
  • Gram -ve
  • Rod
  • Oxidase negative, catalase positive
  • Oportunistic pathogen
39
Q

Give the Gram type, morphology and biochemical features of Sterptococcus beta-haemolytic

A
  • Gram +ve
  • Coccoid
  • Oxidase and catalase negative, facultative anaerobes
  • Completely haemolytic
40
Q

When is immunde defence likely to be at its weakest in relation of hormones?

A

Weakest where progesterone is highest as progesterone is anti-inflammatory

41
Q

What situations in reproductive biology may result in the stimulation of the immune system?

A
  • Copulation
  • Cervix being open
  • Parturition
  • Presence of foetus