Antibodies medical comic

This comic takes you into the 'gamma sector' to meet the immunoglobulins. It covers the Y-shaped structure, what enzymes do to it, the five classes and their jobs, how a limited set of genes makes millions of antibodies, what goes wrong in myeloma, and how hybridoma technology makes monoclonal antibodies.

For MBBS, NEET-PG, FMGE, NEXT and USMLE revision.

Antibodies: what the comic covers

High-yield points

Antibodies are Y-shaped glycoproteins made by plasma cells; they run in the gamma-globulin fraction on serum electrophoresis.
Each has two identical heavy chains and two identical light chains joined by disulphide bonds.
Papain cuts an antibody into two Fab fragments and one Fc fragment; pepsin leaves the two arms joined as F(ab')2.
Fab carries the hypervariable regions that bind antigen; Fc decides effector functions such as complement fixation and binding to cells.
IgG is the most abundant, lives longest (about 23 days) and is the only class that crosses the placenta.
IgM is a pentamer with 10 binding sites, the first antibody made and the best at fixing complement; IgA guards mucosa and breast milk; IgE binds mast cells and basophils in allergy and worm infection.
Diversity comes from V(D)J recombination of gene segments; heavy-chain genes are on chromosome 14.
Multiple myeloma produces excess light chains — Bence Jones proteins; hybridomas (B cell fused with myeloma cell, selected in HAT medium) make monoclonal antibodies, now humanised to avoid anti-mouse reactions.

Mnemonics from the comic

IgM: IgM: Massive Macroglobulin, made first in Minutes.
Hybridoma selection: HAT medium Highlights Awesome Tumours.
Classes: GAMED — IgG, IgA, IgM, IgE, IgD.

Quick questions

Which antibody crosses the placenta?

IgG is the only immunoglobulin class that crosses the placenta, giving the newborn passive immunity for its first months.

What do papain and pepsin do to antibodies?

Papain splits an antibody into two Fab fragments and one Fc fragment. Pepsin cuts below the hinge, leaving one F(ab')2 fragment that still binds two antigens.

How are monoclonal antibodies made?

Antibody-making B cells are fused with myeloma cells to make hybridomas. HAT medium kills unfused myeloma cells, and unfused B cells die naturally, leaving immortal clones that make one antibody.

Is this comic free to read?

The first pages are free to preview. Members read the full comic, and you can sign up free to read one comic in full.