B lymphocytes and humoral immunity Flashcards
What is humoral immunity?
It is a type of immune response involving antibodies, which are soluble in blood and tissue fluid
How many different types of B cells exist?
There are millions of B cells, each producing a specific antibody for a particular antigen
How does a B cell recognise an antigen?
Each B cell has an antibody on its surface that is complementary to a specific antigen
What happens when a B cell binds to its complementary antigen?
The antigen is taken into the B cell by endocytosis and then processed and presented to its surface
What stimulates the B cell to divide after antigen presentation?
T helper cells (Th cells) bind to the processed antigen and stimulates mitotic division of the B cell
What is clonal selection?
The process where a specific B cell is activated, divides by mitosis, and forms identical clones that produce the required antibody
Why do pathogens trigger multiple B cell responses?
Pathogens have multiple antigens on their surface and may also produce toxins, each acting as an antigen
What are monoclonal antibodies?
Antibodies produced by a single clone B cells, each targeting one specific antigen
What are the two types of B cell clones that form after activation?
Plasma cells and memory cells
What is the function of plasma cells?
They secrete antibodies into blood plasma to help destroy the pathogen
How long do plasma cells live?
Only a few days
How many antibodies can a plasma cell produce per second?
Around 2000 antibodies per second
What is the primary immune response?
The initial production of plasma cells and antibodies during the first exposure to an antigen
What is the function of memory cells?
They provide long term immunity by responding rapidly to future infections with the same antigen
How long do memory cells live?
Decades or even a lifetime
What happens when memory cells re-encounter the same antigen?
They divide rapidly, forming new plasma cells and more memory cells
How does the secondary immune response differ from the primary response?
It is faster and produces more antibodies, preventing infection before symptoms appear
