Chapter 2 (page 13) Flashcards
What stage in development of B-cells does changing of immature B-cells into an activated B cell occur?
Second stage
B - cell goes through __________ , which forms clones of the original B-cell and antigen, resulting in numerous cells all descended from one ancestor cell.
Mitosis
What will happen once the immature B-cell migrates to nodes, liver or spleen?
they wait until they encounter a specific antigen. Once they encounter the antigen, they bind to it.
__________ are triggered to change only if they come in contact with antigens whose ‘lock fits their key’. Once lock and key fit together, the ______________ becomes activated.
B-cells
immature B cell
Activated B-cell then divides into many clones of two types:
Plasma cells
Memory cells
It is the function of Plasma cells:
It secrete antibodies into blood to form an army of protection.
_____________ remain in reserve until they encounter the same antigen that helped to form them. They can quickly secrete antibodies to bind with antigens
and kill bacteria.
Memory cells
Function of B-cells:
Indirectly produce humoral immunity by secreting antibodies into blood.
___________ – When B-cells encounter antigens and produce antibodies against them, this is _____________.
Active Immunity
active humoral immunity
Active immunity through infection – contact with a pathogen
Naturally acquired
Active immunity through vaccine – dead or attenuated pathogens
Artificially acquired
What is Passive Humoral Immunity?
antibodies are obtained from the serum of an immune human
or animal donor.
Passive immunity by antibodies passing from mother to fetus via the placenta or to infant through her milk.
Naturally acquired
It is an immunity that is artificially acquired by injection of immune serum.
Passive immunity
Also called immunoglobulins or Igs. They are soluble proteins secreted by activated B-cells and are capable of binding to specific antigens.
ANTIBODIES
How many are Ig classes?
There are 5 Ig classes
Antibodies terminates an antigen in different ways:
Neutralization
Agglutination or Clumping
Antibodies promote and enhance phagocytosis
Complement fixation
What is Neutralization?
Once the antibody-antigen complex is formed the antibodies block specific sites in viruses or bacterial exotoxins. By becoming part of the complex the antigen is neutralized because the antigen can not bind to receptor sites on target cells to cause injury. The complex is eventually destroyed by phagocytes.
Antibodies have more than one antigen binding site, they can bind to one or more antigens at a time. Once the antibody/antigen complex is formed there is a clumping together of the complexes, then ___________ can destroy
them by ingesting them.
Agglutination or Clumping
phagocytes
How antibodies promote and enhance phagocytosis?
Certain antibody fractions help promote the attachment of phagocytic cells to the object they will engulf, therefore contact between phagocytic cells and its victim is enhanced.
What is Complement fixation?
Mechanism in the body used to destroy foreign substances in the body.
