INTRODUCTION TO IMMUNOLOGY Flashcards
EXAMPLES OF WHEN HUMANS ARE STERILE?
THE ZYGOTE IS STERILE
WHEN INSIDE THE AMNIOTIC SAC, WE ARE STERILE
ROLE OF THE IMMUNE SYSTEM?
MAINTAINS THE HOST IN A HEALTHY HOMEOSTASIS WITH THE ENVIRONMENT, PROTECT AGAINST INFECTION, TUMOUR FORMATION ETC.
WHAT IS A SYSTEM?
A GROUP OF INTERACTING OR INTERRELATED ELEMENTS THAT ACT ACCORDING TO A SET OF RULES FROM A UNIFIED WHOLE
- RELY ON FEEDBACK LOOPS TO MAINTAIN A STABLE (FUNCTIONAL) STATE
WHAT IS THE INNATE IMMUNE RESPONSE?
THE FAST, GENETICALLY ENCODED, MEMORYLESS RESPONSE (ALWAYS THE SAME, NO IMPROVEMENT/ADAPTATION)
ONSET AND DURATION OF INNATE RESPONSE?
ONSET: MINUTES AFTER INFECTION
DURATION: UP TO A FEW DAYS
WHAT IS THE ADAPTIVE IMMUNE RESPONSE?
IT’S A SLOWER, SELECTED ‘ON THE FLY’ IMMUNE RESPONSE WHICH HAS ‘MEMORY’
ONSET AND DURATION OF ADAPTIVE IMMUNE RESPONSE?
ONSET: HOURS/DAYS AFTER THE INFECTION
DURATION: UP TO A FEW WEEKS
MOST COMMON PLACE TO GET AN INFECTION?
MOUTH (DENTAL CARIES=)
HOMEOSTASIS DIFFERENCES AMONG INDIVIDUALS?
- HEALTH HOMEOSTASIS ISN’T THE SAME FOR EVERYONE
- THRESHOLD FOR RESPONSE TO INFECTION DIFFERS
- THAT THRESHOLD IS VERY PLASTIC (NOT SET AT BIRTH, CAN CHANGE)
WHAT IS IMMUNOLOGICAL MEMORY?
MAINTENANCE OF MEMORY B CELLS AND T CELLS AND HIGH SERUM OR MUCOSAL ANTIBODY LEVELS, STARTS DAYS TO WEEKS AFTER INFECTION ONSET, CAN BE LIFELONG
WHAT TYPE OF REACTION CAN THE IMMUNE SYSTEM HAVE WHEN THERE’S BACTERIA IN THE BODY?
RESPOND OR TOLERATE (IMBALANCE IN THIS RESPONSE LEADS TO DISEASE)
MAJORITY OF THE INFECTIONS ARE STOPPED BY WHICH MECHANISMS?
PHYSICAL BARRIERS AND INNATE RECOGNITION AND RESPONSE
CAN THE ADAPTIVE IMMUNE RESPONSE BE INITIATED WITHOUT PRIOR INITIATION OF THE INNATE RESPONSE?
NO
STEM CELL FROM WHICH THE CELLS OF THE IMMUNE SYSTEM COME?
MULTIPOTENTIAL HEMATOPOIETIC STEM CELL (HEMOCYTOBLAST)
WHICH CELL DO ALL INNATE IMMUNE CELLS COME FROM?
COMMON MYELOID PROGENITOR
WHICH CELL DO ALL ADAPTIVE IMMUNE CELLS COME FROM?
COMMON LYMPHOID PROGENITOR
INNATE IMMUNE CELLS EXAMPLES:
THROMBOCYTE, MACROPHAGE, DENDRITIC CELLS, NEUTROPHILS, BASOPHILS, MAST CELLS, ERYTHROCYTES
ADAPTIVE IMMUNE CELLS EXAMPLES:
T LYMPHOCYTE, B LYMPHOCYTE, PLASMA CELL, LARGE GRANULAR LYMPHOCYTE…
TOPOLOGICALLY, HUMANS ARE A
CYLINDER
SURFACES OF OUR BODY THAT MOST INTERACT WITH THE ENVIRONMENT ARE MOST LIKELY TO GET INFECTED, WHAT ARE THE EXAMPLES OF THESE SURFACES?
- RESPIRATORY, REPRODUCTIVE AND GI TRACT
- WOUNDS, ABRASIONS AND BITES THAT DISRUPT ANATOMICAL BARRIERS
WHAT ARE IMMUNE PRIVILEGED SITES?
PARTS OF THE BODY WERE YOU WOULDN’T EXPECT TO GET AN INFECTION/MOST ANTIGENS CAN’T PRODUCE AN IMMUNE RESPONSE THERE
BRAIN (CNS), EYES, OVARIES AND TESTES
PHYSICAL PROPHYLAXIS:
- EPITHELIAL SURFACES ARE THE 1ST ANATOMICAL BARRIER TO INFECTION (SKIN EPIDERMIS, GUT EPITHELIUM, BRONCHIAL CILIATED EPITHELIUM)
- CHEMICAL BARRIERS ARE ALSO PRESENT (LYSOZYME IN TEARS AND SALIVA, MUCUS, ACID IN THE STOMACH, ANTI MICROBIAL PEPTIDES…)
INNATE CELLS ARE USUALLY PHAGOCYTIC, WHAT DOES THAT MEAN ABOUT THEIR FUNCTIONING?
THEY ‘EAT’ CELLS TO SIMPLY REMOVE THE MICROBE AND DESTROY IT
WHAT ARE NEUTROPHILS?
SHORT LIVED BUT EFFECTIVE INNATE EFFECTOR CELLS THAT CAN MAKE EXTRACELLULAR TRAPS (NETs) FROM EXCRETED DNA TO CAPTURE BACTERIA
HOW DO INNATE CELLS DETECT INFECTIOUS AGENTS?
THEY CAN DIRECTLY DETECT INFECTIOUS AGENTS THROUGH GENETICALLY ENCODED RECEPTORS CALLED ‘SENSORS’
WHAT ARE ‘SENSORS’ OF INNATE CELLS AND WHERE CAN THEY BE LOCATED?
SENSORS ARE PATTERN RECOGNITION RECEPTORS (PRRs) WHICH CAN BE MEMBRANE BOUND OR IN THE CYTOPLASM
EXAMPLES OF MEMBRANE BOUND PATTERN RECOGNITION RECEPTORS (INNATE CELL ‘SENSORS’):
TOLL LIKE RECEPTORS (TLRs)
C-TYPE LECTIN RECEPTORS (CLRs)
EXAMPLES OF CYTOPLASMIC PATTERN RECOGNITION RECEPTORS (INNATE CELL ‘SENSORS’):
NOD-LIKE RECEPTORS (NLRs)
RIG-I-LIKE RECEPTORS (RLRs)
2 MAIN TYPES OF LYMPHOCYTES (WHITE BLOOD CELLS)
T CELLS AND B CELLS
WHICH CELLS ARE THE GATEKEEPERS OF THE ADAPTIVE IMMUNE RESPONSE?
T CELLS
WHERE DO T CELLS PRIMARILY DEVELOP?
THE THYMUS
HOW DID THE T CELLS GET THEIR NAME?
T COMES FROM THEIR SITE OF PRODUCTION, THE THYMUS
WHAT ARE THE ACTIVATED T CELLS CALLED?
EFFECTOR T CELLS
FUNCTIONS OF EFFECTOR T CELLS:
- CAN BE CYTOLYTIC
- CAN LICENCE B CELLS TO ACTIVATE
WHERE ARE B CELLS PRODUCED?
THE BONE MARROW
WHAT DO B CELLS PRODUCE AND WHAT IS THE ROLE OF THIS PRODUCT?
- ANTIBODIES
- THE ANTIBODIES HAVE HIGH AFFINITY FOR BINDING TO PATHOGENS AND THEY CAN BLOCK THEIR FUNCTION OR EXPOSE THEM TO INNATE RESPONSE FOR KILLING
WHICH TYPE OF IMMUNE RESPONSE IS LACKING IN BABIES AND HOW DO THEY ACQUIRE ANTIBODIES?
ADAPTIVE RESPONSE
BREAST MILK IS A SOURCE OF ANTIBODIES
ROLE OF T CELL ANTIGEN RECEPTORS (TCRs):
RECOGNISE SHORT PEPTIDES FROM PATHOGENIC PROTEINS
ROLE OF B CELL ANTIGEN RECEPTORS (ANTIBODIES):
RECOGNISE PATHOGEN STRUCTURES
T CELL AND B CELL ANTIGEN RECEPTORS: HOW ARE THEY FORMED?
- TCRs AND BCRs ARE NOT GENETICALLY ENCODED
- THROUGH THE PROCESS OF SOMATIC GENE RECOMBINATION, ALMOST LIMITLESS POTENTIAL RECEPTORS CAN BE ENCODED, DEPENDING ON THE ANTIGEN
HOW ARE RECEPTOR GENES CREATED (FOR T CELL AND B CELL ANTIGEN RECEPTORS)?
USING V(D)J SOMATIC RECOMBINATION, WHICH ‘STITCHES’ GENETIC FRAGMENTS TOGETHER TO CREATE A UNIQUE GENE
HOW DO TCRs DIFFER AMONG T CELLS?
- ALMOST NONE HAVE THE SAME TCRs
- EACH ONE IS A CLONOTYPE (a unique nucleotide sequence that arises during the gene rearrangement process for that receptor)
WHICH ENZYMES INITIATE V(D)J SOMATIC RECOMBINATION DURING IMMUNE CELL DEVELOPMENT TO HELP LYMPHOCYTE ANTIGEN RECEPTOR CREATION?
RAG1/2 ENZYMES
ACTIVATED T CELLS WHICH PROVIDE HELP TO OTHER IMMUNE CELLS (LIKE B CELLS) ARE CALLED:
HELPER T CELLS
ACTIVATED T CELLS WHICH KILL INFECTED CELLS BY DIRECT RECOGNITION ARE CALLED?
CYTOTOXIC T CELLS
WHAT IS THE MOLECULAR BRIDGE BETWEEN INNATE AND ADAPTIVE RESPONSE?
- PEPTIDES DERIVED FROM PATHOGENS ARE ‘PRESENTED’ ON SURFACE IN MHC COMPLEX
- THE T CELL INTERACTION WITH PEPTIDE-MHC IS THE MOLECULAR BRIDGE BETWEEN INNATE AND ADAPTIVE RESPONSE
ANTIBODY MEDIATED EFFECTOR (ACTIVATED LYMPHOCYTES) FUNCTIONS:
NEUTRALISATION (BLOCKING VIRUS ENTRY INTO CELLS OR BLOCKING TOXIN ACTION)
OPSONISATION (COATING MICROBES TO ALLOW THEIR EFFICIENT UPTAKE)
COMPLEMENT ACTIVATION (DIRECT LYSIS OF MICROBE)
