Adaptive immunity Flashcards Preview

Microbiology > Adaptive immunity > Flashcards

Flashcards in Adaptive immunity Deck (17):
1

Adaptive immunity is?

The body’s ability to recognize and defend itself against distinct invaders and their products

2

Five attributes of adaptive immunity (AI)

– Specificity-Any response acts against one particular molecular shape & not to others. Precisely tailored reactions against specific attackers
– Inducibility- cells of AI activate only in response to specific pathogens
– Clonality- Once induced, cells of AI, proliferate to form many generations of almost identical cells called clones
– Unresponsiveness to self- AI doesn't act against normal body cells, AI responses are self-tolerant
– Memory- AI response has memory about specific pathogens, it adapts to respond faster & more effectively in subsequent encounters w/a particular type of pathogen or toxin

3

Adaptive immunity involves activity of which cells?

Lymphocytes, a type of leukocyte (WBC), that acts against specific pathogens. Lymphocytes in their resting state are the smallest WBCs, & each characterized by a large, round, central nucleus surrounded by a thin rim of cytoplasm

4

Two main types of lymphocytes

1) B lymphocytes (B cells)– Mature in the bone marrow
2) T lymphocytes (T cells)– Mature in the thymus

5

Two types of adaptive immune responses

– Humoral immune responses
– Cell-mediated immune responses

6

The Tissues and Organs of the Lymphatic System

Composed of lymphatic vessels (conduct flow of liquid called lymph) and lymphatic cells, tissues, and organs which are directly involved in AI. Screen the tissues of the body for foreign antigens

7

How can you distinguish between B-lymphocytes and T-lymphocytes?

According to integral surface proteins that are part of each lymphocytes cytoplasmic membrane. These proteins allow lymphocytes to recognized specific pathogens and toxins by their molecular shapes, and the proteins play roles in intercellular communication among immune cells

8

Where do B and T cells arise and mature

B-cells- arise & mature in red bone marrow of adults
T-cells arise in red bone marrow but mature in the thymus located in the chest near the heart

9

The two types of adaptive immune responses are humoral and cell-mediated, describe humoral

Immune activity centered in bodily fluids such as blood (humors, latin word for moisture), is called humoral immune responses. Descendants of activated B cells are the main defensive cells of this response. Once induced, B cells secrete soluble proteins called antibodies that act againsts extracellular pathogens such as bacteria & fungi in the body's fluids

10

The two types of adaptive immune responses are humoral and cell-mediated, describe cell-mediated immunity

Descendants of T-cells regulate AI responses or attack intracellular pathogens, such as viruses replicating inside a cell. Such T-lymphocytes mount cell-mediated immune responses which do not involve antibodies

11

What role does the lymphatic system play?

The production, maturation, and housing of the cells that function in adaptive immunity

12

The Tissues and Organs of the Lymphatic System
– Lymphatic vessels and the flow of lymph

– Conducts lymph from tissues and returns it to the
circulatory system
– Lymph- Liquid with similar composition to blood plasma. Arises from fluid leaked from blood vessels into surrounding tissues. Contains wastes such as degraded proteins & toxins. Only flows in one direction towards heart

13

What are lymph nodes

Located at various points within the system of lymphatic vessels are about 1000 lymph nodes, which house leukocytes that recognize and attack foreigners present in lymph, allowing for immune system surveillance and interactions

14

The Tissues and Organs of the Lymphatic System

– Lymphoid organs
1) Primary lymphoid organs
– Red bone marrow
– Thymus
2) Secondary lymphoid organs
– Lymph nodes
– Spleen
– Tonsils
– Mucosa-associated lymphatic tissue (MALT)

15

Antigens

– Properties of antigens
– Molecules the body recognizes as foreign and worthy of attack
– Recognized by three-dimensional regions called epitopes
– Include various bacterial components as well as proteins of viruses, fungi, and protozoa
– Food and dust can also contain antigenic particles

16

B Lymphocytes (B Cells) and Antibodies

– Arise and mature in the red bone marrow
– Found primarily in the spleen, lymph nodes, and MALT
– Small percentage of B cells circulates in the blood
– Major function is the secretion of antibodies

17

B Lymphocytes (B Cells) and Antibodies

– Specificity of the B cell receptor (BCR)
– Each B lymphocyte has multiple copies of the B cell
receptor
– Each B cell generates a single BCR
– Two variable regions of the BCR form the antigenbinding
sites
– Each BCR recognizes only one epitope
– Individual’s repertoire of BCRs is capable of recognizing millions of different epitopes