For every Google+ account, there will be a particular profile page with a URL like the following:
The user number "114785135385262933560" also called profile ID. You can add the above URL in your Google Reader and subscribe to the user’s Buzz, but not Google+. To subscribe a Google+ user’s public profile status, you can check out the PlusFeed website.
On the homepage, there is an instruction that shows you how PlusFeed works, you can copy and paste the profile ID into the end of the website’s URL, such as the following:
Press the Enter key, you will see an Atom feed, add the URL of which to your Google Reader, then you can subscribe to the user’s Google+ profile status.
By the way, don’t add "/" in the end of the profile ID, or you will get an error page. And you can read only one Google+ user’s public profile status for one feed.