Images of CD4
![Generation and Immune Regulation of CD4+CD25−Foxp3+ T Cells in Chronic Obstructive Pulmonary Disease](https://www.frontiersin.org/files/Articles/427847/fimmu-10-00220-HTML-r2/image_m/fimmu-10-00220-g008.jpg)
Generation and Immune Regulation of CD4+CD25−Foxp3+ T Cells in Chronic Obstructive Pulmonary Disease
![Without CD4+ T cell help, cytotoxic effectors would not existSmall change for you. Big change for us!](https://acir.org/uploads/CD4_Tcell_help_small.jpg)
Without CD4+ T cell help, cytotoxic effectors would not existSmall change for you. Big change for us!
![Illustration shows activation of a CD4-plus helper T cell. An antigen-presenting cell digests a pathogen. Epitopes from this pathogen are presented in conjunction with MHC II molecules on the cell surface. A T cell receptor and a CD8 receptor, both on the surface of the T cell, bind the MHC II-epitope complex. As a result, the helper T cell becomes activated and both the helper T cell and antigen-presenting cell release cytokines. The cytokines induce the helper T cell to clone itself. The cloned helper T cells release different cytokines that activate B cells and CD8+ T cells, turning them into cytotoxic T cells. The cytotoxic and binds the MHC I-epitope complex on an infected cell. The cytotoxic T cell then releases perforin molecules, which form a pore in the plasma membrane, and granzymes, which break down proteins, killing the cell.](https://s3-us-west-2.amazonaws.com/courses-images/wp-content/uploads/sites/1223/2017/02/09171205/Figure_42_02_04-1024x903.png)
Illustration shows activation of a CD4-plus helper T cell. An antigen-presenting cell digests a pathogen. Epitopes from this pathogen are presented in conjunction with MHC II molecules on the cell surface. A T cell receptor and a CD8 receptor, both on the surface of the T cell, bind the MHC II-epitope complex. As a result, the helper T cell becomes activated and both the helper T cell and antigen-presenting cell release cytokines. The cytokines induce the helper T cell to clone itself. The cloned helper T cells release different cytokines that activate B cells and CD8+ T cells, turning them into cytotoxic T cells. The cytotoxic and binds the MHC I-epitope complex on an infected cell. The cytotoxic T cell then releases perforin molecules, which form a pore in the plasma membrane, and granzymes, which break down proteins, killing the cell.