My question is what 22 shell would be good for home defense if that's all you have.
Any good high velocity .22 round like Remington Golden .22s.
See the .22 for home defense relies on accurate shot placement more than anything.
A good Ruger 10/22 rifle with 10 to 25 round mags makes a real good HD long gun (I prefer the 16 bbl 'bantam' versions myself for this) and a reliable .22 pistol also.
Good thing is you can actually practice with your HD ammo alot (well you will once the ammo craze dies down.)