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Biology a level immunity panic

So I'm really struggling with immunity can any one please explain what the cellular and humoural response is and also the primary and secondary response is ???
It would be a great help or guide me to helpful resources?
Thank you in advance
Original post by Sparky2016
So I'm really struggling with immunity can any one please explain what the cellular and humoural response is and also the primary and secondary response is ???
It would be a great help or guide me to helpful resources?
Thank you in advance


Immunity is mediated by two types of response: Cellular and Humoural.

Cellular is the first line of defense, involving phagocytes(they engulf debris and pathogens) that move to site of the site of infection and eat up pathogens. This is how your body learn to recognise pathogens and will immediately recognise them next time (via antigens).

Humoural is the second step to all this, if your cellular response is not enough to kill off all the pathogens. This happens when phagocytes and antigen presenting cells (APCs) take up the debris containing antigens. They then present them to your T cells which activates your innate immune system. This activates B cells and they start producing antibodies which are makes killing those pathogens more efficient. Some B cells will become memory cells which will 'remember' the pathogen and can be quickly activated the next time you meet that same pathogen.

Primary response refers to your body's reaction to meeting the pathogens for the first time, it takes time for body to process the antigens and to produce antibodies. The next time your body is exposed to the same pathogens (and their antibodies) your memory B cells will quickly recognise it and produce antibodies much quicker than primary response. This is called secondary response.

Sorry this is a really brief summary but you should checkout khan academy and Kurzgesagt- in a nutshell on youtube, they've got some videos on immunity. To be honest if this is for AS bio, you're better off learning the mark scheme once you understand the basic concepts.
Reply 2
Original post by Sparky2016
So I'm really struggling with immunity can any one please explain what the cellular and humoural response is and also the primary and secondary response is ???
It would be a great help or guide me to helpful resources?
Thank you in advance


Cellular response - Involves T lymphocytes - T helper cell is activated when it comes across a complementary antigen on an antigen-presenting cell, like a phagocyte. It then divides rapidly by mitosis into cytotoxic T cells(Kills pathogens by injecting perforin into its cell wall, and causes lysis of the cell)
It also activates B cells to divide by mitosis to form plasma cells and memory cells.

Humoral response - Involves B lymphocytes - B cell activated to divide by mitosis by T helper cell. It forms Plasma Cells and Memory Cells.

Primary response (First time your immune system encounters the antigen) - Initial response to the antigen, Plasma Cells (Produces antibodies - 2000 per second) and Memory Cells are created from mitosis of the activated B lymphocyte.

Secondary response (When the immune system encounters the same antigen again) - Memory cells that are complementary to the antigen, divide rapidly by mitosis, and form plasma cells and more memory cells.
Reply 3
Original post by BlueIsTheNewRed
Immunity is mediated by two types of response: Cellular and Humoural.

Cellular is the first line of defense, involving phagocytes(they engulf debris and pathogens) that move to site of the site of infection and eat up pathogens. This is how your body learn to recognise pathogens and will immediately recognise them next time (via antigens).

Humoural is the second step to all this, if your cellular response is not enough to kill off all the pathogens. This happens when phagocytes and antigen presenting cells (APCs) take up the debris containing antigens. They then present them to your T cells which activates your innate immune system. This activates B cells and they start producing antibodies which are makes killing those pathogens more efficient. Some B cells will become memory cells which will 'remember' the pathogen and can be quickly activated the next time you meet that same pathogen.

Primary response refers to your body's reaction to meeting the pathogens for the first time, it takes time for body to process the antigens and to produce antibodies. The next time your body is exposed to the same pathogens (and their antibodies) your memory B cells will quickly recognise it and produce antibodies much quicker than primary response. This is called secondary response.

Sorry this is a really brief summary but you should checkout khan academy and Kurzgesagt- in a nutshell on youtube, they've got some videos on immunity. To be honest if this is for AS bio, you're better off learning the mark scheme once you understand the basic concepts.


Thanks so much! I would do that but it's a new spec so there's no past papers which has made revision harder , we've done a specimen paper though and that didn't cover much on this
Reply 4
Original post by JGang
Cellular response - Involves T lymphocytes - T helper cell is activated when it comes across a complementary antigen on an antigen-presenting cell, like a phagocyte. It then divides rapidly by mitosis into cytotoxic T cells(Kills pathogens by injecting perforin into its cell wall, and causes lysis of the cell)
It also activates B cells to divide by mitosis to form plasma cells and memory cells.

Humoral response - Involves B lymphocytes - B cell activated to divide by mitosis by T helper cell. It forms Plasma Cells and Memory Cells.

Primary response (First time your immune system encounters the antigen) - Initial response to the antigen, Plasma Cells (Produces antibodies - 2000 per second) and Memory Cells are created from mitosis of the activated B lymphocyte.

Secondary response (When the immune system encounters the same antigen again) - Memory cells that are complementary to the antigen, divide rapidly by mitosis, and form plasma cells and more memory cells.


Thanks, so you is the cell mediated response cover both the humoural response and the cellular response ?
Reply 5
Original post by Sparky2016
Thanks, so you is the cell mediated response cover both the humoural response and the cellular response ?


No, just cellular I think.
Reply 6
Original post by JGang
No, just cellular I think.


Okay :smile:

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