Immunity

I don’t really understand T-cells

but when my doctor describes them,

I imagine T’s posted at intervals

in my bloodstream, like sentries

at a crenellated wall. 

Are they T-shaped?

Or is T merely the first initial

of a long, inscrutable, Latin word?

I see a line of cells holding shields

emblazoned with Ts.

I hear their rhythmic chant,

T - T - T - T - T,

as they fall into formation

for their regular bloodstream drills.