Immune Response — Innate + Adaptive

digraph imm {
  rankdir=TB;
  graph [bgcolor=transparent];
  node [shape=box, style="rounded,filled", fontname=Inter, fontsize=10];

  Path [label="Pathogen", fillcolor="#fee2e2"];
  Bar [label="Barriers\n(skin, mucosa)", fillcolor="#dbeafe"];
  Inn [label="Innate response\n(macrophages, NK, complement)", fillcolor="#fef3c7"];
  APC [label="Antigen-presenting cell"];
  T [label="T cells", fillcolor="#dcfce7"];
  TH [label="T helper (CD4+)"];
  TC [label="Cytotoxic T (CD8+)"];
  B [label="B cells", fillcolor="#dcfce7"];
  Plasma [label="Plasma cells → antibodies"];
  Mem [label="Memory cells", fillcolor="#fce7f3"];

  Path -> Bar [label="enter?"];
  Bar -> Inn [label="breached"];
  Inn -> APC [label="phagocytose +\nMHC present"];
  APC -> T;
  T -> TH; T -> TC;
  TH -> B [label="activates"];
  B -> Plasma;
  TC -> Path [label="kill infected cells", style=dashed];
  Plasma -> Path [label="neutralise", style=dashed];
  TH -> Mem; B -> Mem; TC -> Mem;
}