What are the cells that cause a type 1 hypersensivity Gram negative cells B-cells Dendritic cells Basophils

The cells that cause a type 1 hypersensitivity reaction are B-cells.

Here's a step-by-step explanation:

1. An allergen (a substance that triggers an allergic reaction) enters the body.
2. Dendritic cells, a type of immune cell, capture the allergen and present it to B-cells.
3. B-cells are a type of white blood cell that produce antibodies against the allergen. In the case of a type 1 hypersensitivity reaction, the B-cells produce a specific type of antibody known as IgE.
4. The IgE antibodies bind to the surface of mast cells and basophils, another type of white blood cell.
5. When the allergen enters the body again, it binds to the IgE antibodies on the mast cells and basophils. This triggers these cells to release substances such as histamine, which cause the symptoms of an allergic reaction.

So, while B-cells, dendritic cells, and basophils all play a role in a type 1 hypersensitivity reaction, it is the B-cells that are primarily responsible for causing the reaction. Gram negative cells are not directly involved in type 1 hypersensitivity reactions.