The viral antigens decided on a battle,
The 'guinea pig' Homo sapien was forced to settle,
The battle of supremacy, the battle royal,
To test the immune system, if it was loyal.

The influenza virus showed its might,
Immunoglobulin M, G and A rose to fight.
The GALT and the BALT rose in union
With the Peyer's patches in the ileum.

Then the measles virus found its way,
NK cells decided to sway,
Armed with granzyme and perforin,
The virions could do nothing but refrain

Mumps virus thought it best,
To follow measles in the test.
CMI sent out the magic interferon,
Virally infected cells were taken head on.

HIV virus was the last to enter
The immune system was hit in the center
T helper cells were alarmingly fading,
T suppressor cells on the contrary kept on rising.

Seeing the immune system crack,
The Homo sapien decided to act,
Doses of HAART he forced into him,
Which controlled the viral replication, or so it
seemed.

All this left the poor human weakened,
In spite of relief he was sickened,
Then crept in death, the unexpected guest
Thus putting an end to the Homo sapiens life quest!