Output html source tags inside shortcode

Try the following code:

function caption_shortcode( $atts, $content = null ) {
    $content = do_shortcode($content);
    return '<span itemprop="articleSection">'. str_replace( array( '<', '>' ), array( '&lt;', '&gt;' ), $content ) .'</span>';
}
add_shortcode( 'source', 'caption_shortcode' );

remove_filter( 'the_content', 'wpautop' );
remove_filter( 'the_excerpt', 'wpautop' );