Apparently 3 strains were identified and the first strain seemed to protect from the more dangerous second and third strains:
That paper analyses the origin of the strains observed in NYC (spoiler: most came from Europe). The paper doesn't discuss at all the "dangerousness" of the strains. One could have spread more simply because more travellers arrived to NYC from Europe than from Washington state (the 2nd most common source/strain) or any other locally favorable factors. (For example, two prior "failed" introductions were one from the Middle East and another one from Europe. The paper doesn't discuss why these didn't spread in NTC, e.g. whether it was effective quarantine of the person carrying them, or some other [lucky] reason.)
Also there's not discussion on immunity whatsoever in the paper, so drawing any conclusions from there as to antibodies for which strain protect against which [other] is completely unsupported by that paper.