What is the referent of “body of Christ” in 1 Corinthians 11:29?

   26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord’s death till he come.

   27 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord.

   28 But let a man examine himself, and so let him eat of that bread, and drink of that cup.

   29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord’s body.

shew - preach or declare.

Eating and drinking the elements preaches the death of Christ and all it's implications.

Therefore an examination of ourselves determines whether our life really reflects that belief. Have we forgiven as we have been forgiven. Do we love as we have been loved. If not, then partaking of the elements without discretion makes one a 'swine':

   Pr 11:22 ¶ [As] a jewel of gold in a swine’s snout, [so is] a fair woman which is without discretion.

   Mt 7:6 Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.

   Le 11:7 And the swine, though he divide the hoof, and be clovenfooted, yet he cheweth not the cud; he [is] unclean to you.

In this case, the body of Christ is the church as in all other cases. Upon examination of oneself, if you do not discern that you are loving and forgiving, then you have discerned that you are not the body of Christ, and are under damnation.

The damnation does not come from taking the elements. You have discerned that you are damned by the examination prior to taking the elements. The cross saves us or judges us based upon whether we are the body of Christ or not. When you discern that you are not the body of Christ and partake of the elements, you are preaching your own damnation.